Volume 36,Issue 6,2007 Table of Contents
1 Interfacial Reaction Diffusion Coefficients and Micro-Diffusion Mechanism in SiC/Ti6AI4V Composite
2007, 36(6):941-948.
Abstract:
采用三元体系半无限扩散偶的高斯方法，求解了SiC／Ti6A14V复合材料界面反应层中相关元素的扩散系数，计算的浓度分布和实测值一致。碳原子通过反应层的扩散服从间隙扩散机制，硅原子的扩散为空位扩散机制。由于碳扩散的振动能最低并且跃迁距离最短，而供硅扩散的空位不足，碳和硅在反应产物TiC，中具有最小的内禀扩散系数，分别为8．9403×10^-16和4．7747×10^-16·m^2·s^-1。研究表明，在SiC／Ti6A14V复合材料界面反应的过程中，反应元素通过反应层TiCx的扩散是一个主要的控制步骤。
采用三元体系半无限扩散偶的高斯方法，求解了SiC／Ti6A14V复合材料界面反应层中相关元素的扩散系数，计算的浓度分布和实测值一致。碳原子通过反应层的扩散服从间隙扩散机制，硅原子的扩散为空位扩散机制。由于碳扩散的振动能最低并且跃迁距离最短，而供硅扩散的空位不足，碳和硅在反应产物TiC，中具有最小的内禀扩散系数，分别为8．9403×10^-16和4．7747×10^-16·m^2·s^-1。研究表明，在SiC／Ti6A14V复合材料界面反应的过程中，反应元素通过反应层TiCx的扩散是一个主要的控制步骤。
2 Interfacial Reaction
Diffusion Coefficients and Micro-Diffusion Mechanism in SiC/Ti6A14V Composite
2007, 36(6):941-948.
Abstract:
采用三元体系半无限扩散偶的高斯方法,求解了SiC/Ti6AL4V复合材料界面反应层中相关元素的扩散系数,计算的浓度分布和实测值一致.碳原子通过反应层的扩散服从间隙扩散机制,硅原子的扩散为空位扩散机制.由于碳扩散的振动能最低并且跃迁距离最短,而供硅扩散的空位不足,碳和硅在反应产物TiCx中具有最小的内禀扩散系数,分别为8.9403×10-16和4.7747×10-16 m2·s-1.研究表明,在SiC/Ti6AL4V复合材料界面反应的过程中,反应元素通过反应层TiCx的扩散是一个主要的控制步骤.
采用三元体系半无限扩散偶的高斯方法,求解了SiC/Ti6AL4V复合材料界面反应层中相关元素的扩散系数,计算的浓度分布和实测值一致.碳原子通过反应层的扩散服从间隙扩散机制,硅原子的扩散为空位扩散机制.由于碳扩散的振动能最低并且跃迁距离最短,而供硅扩散的空位不足,碳和硅在反应产物TiCx中具有最小的内禀扩散系数,分别为8.9403×10-16和4.7747×10-16 m2·s-1.研究表明,在SiC/Ti6AL4V复合材料界面反应的过程中,反应元素通过反应层TiCx的扩散是一个主要的控制步骤.
2007, 36(6):949-953.
Abstract:
采用G1eeble-1500热模拟实验机，对2195铝锂合金变形温度为360～520℃，应变速率为0．001-1．0s^-1的单道次热压缩及变形温度为320℃和360℃，应变速率为0．1s^-1，道次间隔时间30-180s的双道次热压缩的流变应力及静态软化规律进行了模拟研究。通过对幂指数应力函数中系数A和β与应变关系的分析，以及采用平均软化法考虑前一道次变形的残余应变对后一道次变形的影响，建立了2195铝锂合金多道次热变形的流变应力方程。
采用G1eeble-1500热模拟实验机，对2195铝锂合金变形温度为360～520℃，应变速率为0．001-1．0s^-1的单道次热压缩及变形温度为320℃和360℃，应变速率为0．1s^-1，道次间隔时间30-180s的双道次热压缩的流变应力及静态软化规律进行了模拟研究。通过对幂指数应力函数中系数A和β与应变关系的分析，以及采用平均软化法考虑前一道次变形的残余应变对后一道次变形的影响，建立了2195铝锂合金多道次热变形的流变应力方程。
Zhang Peixin
,
Wen Yanxuan
,
Liu Jianhong
,
Xu Qiming
,
Ren Xiangzhong
,
Zhang Qianling
,
Luo Zhongkuan
2007, 36(6):954-958.
Abstract:
The chemical co-precipitation method was used to synthesize LiFePO4 by doping with Mg2+,Al3+,Ti4+,V5+,and Ni 2+,then the specific charge/discharge capacity of LiFePO4 was measured by stable-current charge/discharge method and the particle structure was examined by X-ray diffraction and Rietveld method. The results indicate that a small amount of metal ion doping can improve the discharge capacity of LiFePO4 to above 120 mAh/g at high current and keeping the capacity over 80% after 20 cycles when the charge/discharge rate is at 2C for Li1-xTixFePO4,Li1-xVxFePO4 and Li1-xNixFePO4,mainly due to the metal ion dopings in the form of solid solution and occupying the position of Lithium. The metal ion dopings change the distance and position between atoms in grains,resulting in the contraction of unit cells,the increase of average distance between Li-O atoms and the disengagement of Lithium ions.
The chemical co-precipitation method was used to synthesize LiFePO4 by doping with Mg2+,Al3+,Ti4+,V5+,and Ni 2+,then the specific charge/discharge capacity of LiFePO4 was measured by stable-current charge/discharge method and the particle structure was examined by X-ray diffraction and Rietveld method. The results indicate that a small amount of metal ion doping can improve the discharge capacity of LiFePO4 to above 120 mAh/g at high current and keeping the capacity over 80% after 20 cycles when the charge/discharge rate is at 2C for Li1-xTixFePO4,Li1-xVxFePO4 and Li1-xNixFePO4,mainly due to the metal ion dopings in the form of solid solution and occupying the position of Lithium. The metal ion dopings change the distance and position between atoms in grains,resulting in the contraction of unit cells,the increase of average distance between Li-O atoms and the disengagement of Lithium ions.
2007, 36(6):959-962.
Abstract:
采用传统固相反应法对水热BaTiO3粉体进行La2O3和Nb2O5双施主复合掺杂，研究（Bal-xLa2x/3）（Til-xNb4x/5）O3陶瓷显微结构特征。结果表明：随着X的增大，晶体结构逐渐由四方相转为立方相。当x≤0．03时，La^3＋、Nb^5＋固溶进入BaTiO3晶格形成单一的钙钛矿相；当x=0．05时，出现Ba6Til7O40富钛第二相；当x≥0．2时，出现Ba-Ti-La-Nb固溶组分的第二相，说明旆主掺杂固溶极限x〈0．2。当x=0．001时，瓷体具有半导化特征，晶粒尺寸为8～10μm；当x≥0．004时，瓷体开始呈现绝缘性，旆主离子表现出明显的抑制晶粒生长作用，随着X增加，晶粒尺寸由10μm（x=0．004）下降至0．5μm（x=0．3）。TEM和EDS分析表明，La^3＋、Nb^5＋双旆主复合掺杂，La^3＋提高了Nb^5＋的扩散固溶能力，相互协同作用使掺杂离子在BaTiO3中分布更均匀。
采用传统固相反应法对水热BaTiO3粉体进行La2O3和Nb2O5双施主复合掺杂，研究（Bal-xLa2x/3）（Til-xNb4x/5）O3陶瓷显微结构特征。结果表明：随着X的增大，晶体结构逐渐由四方相转为立方相。当x≤0．03时，La^3＋、Nb^5＋固溶进入BaTiO3晶格形成单一的钙钛矿相；当x=0．05时，出现Ba6Til7O40富钛第二相；当x≥0．2时，出现Ba-Ti-La-Nb固溶组分的第二相，说明旆主掺杂固溶极限x〈0．2。当x=0．001时，瓷体具有半导化特征，晶粒尺寸为8～10μm；当x≥0．004时，瓷体开始呈现绝缘性，旆主离子表现出明显的抑制晶粒生长作用，随着X增加，晶粒尺寸由10μm（x=0．004）下降至0．5μm（x=0．3）。TEM和EDS分析表明，La^3＋、Nb^5＋双旆主复合掺杂，La^3＋提高了Nb^5＋的扩散固溶能力，相互协同作用使掺杂离子在BaTiO3中分布更均匀。
2007, 36(6):963-967.
Abstract:
利用OM（光学金相）、SEM对损伤容限TC4-DT合金双态组织中的疲劳裂纹扩展行为进行研究。结果表明：裂纹扩展遇到初生口相时，既能以绕过初生口相的方式扩展，又能直接切过初生口相向前扩展；预裂区和快速扩展区主要是以微区解理断裂为主，稳态扩展区主要是以疲劳条带扩展机制为主，同时也存在微区解理断裂机制。
利用OM（光学金相）、SEM对损伤容限TC4-DT合金双态组织中的疲劳裂纹扩展行为进行研究。结果表明：裂纹扩展遇到初生口相时，既能以绕过初生口相的方式扩展，又能直接切过初生口相向前扩展；预裂区和快速扩展区主要是以微区解理断裂为主，稳态扩展区主要是以疲劳条带扩展机制为主，同时也存在微区解理断裂机制。
2007, 36(6):968-972.
Abstract:
采用放电等离子烧结（sps）技术在800～1000K温度范围内，原位反应合成了以ce，La作为填充原子及Ni，Fe作为置换原子的填充式方钴矿化合物REy（Fe／Ni）xCO4xsb12（x=0～1．0，y=0～0．4）。系统研究了填充原子的种类、填充方式以及置换原子的种类对晶格热导率及热电性能的影响。结果表明，在Co位置上Fe或Ni的置换，能显著降低其晶格热导率，与Fe相比，Ni对晶格热导率的影响更显著。在Skutterudite结构sb组成的二十面体空洞填充ce，La原子可以显著降低其晶格热导率，在填充分数相同时，两种稀土原子复合填充较单一原子填充更能有效降低晶格热导率。电导率随ce，La填充分数的增加而降低，Seebeck系数随填充分数的增加而升高。填充分数为0．3的ce0.1La0.2FeCo3Sb12化合物具有最低的晶格热导率和最大的zT值，在800K时达0．6左右。
采用放电等离子烧结（sps）技术在800～1000K温度范围内，原位反应合成了以ce，La作为填充原子及Ni，Fe作为置换原子的填充式方钴矿化合物REy（Fe／Ni）xCO4xsb12（x=0～1．0，y=0～0．4）。系统研究了填充原子的种类、填充方式以及置换原子的种类对晶格热导率及热电性能的影响。结果表明，在Co位置上Fe或Ni的置换，能显著降低其晶格热导率，与Fe相比，Ni对晶格热导率的影响更显著。在Skutterudite结构sb组成的二十面体空洞填充ce，La原子可以显著降低其晶格热导率，在填充分数相同时，两种稀土原子复合填充较单一原子填充更能有效降低晶格热导率。电导率随ce，La填充分数的增加而降低，Seebeck系数随填充分数的增加而升高。填充分数为0．3的ce0.1La0.2FeCo3Sb12化合物具有最低的晶格热导率和最大的zT值，在800K时达0．6左右。
2007, 36(6):973-976.
Abstract:
采用电子束物理气相沉积（EB-PVD）技术，成功制备了尺寸为150mm×100mm的TiAl基合金薄板，并利用光学显微镜（OM）、扫描电子显微镜（SEM）和x射线衍射（XRD）等测试手段，对真空退火或热压前后试样的显微形貌、物相组成等进行了分析。结果表明，蒸镀态TiAl基合金薄板由 γ相、α2相和ι相组成，成分呈梯度变化，内部自然分层，显微组织结构为柱状晶；经1000℃，16h的真空退火处理后，柱状晶和τ相消失，α2相含量显著减少，成分趋于均匀化；而经1250℃，1h的真空热压处理后，材料致密度得到明显提高。TiAl基合金薄板经真空退火或热压处理前后，断裂方式由沿晶断裂转变为解理断裂和沿晶断裂的混合断裂方式。
采用电子束物理气相沉积（EB-PVD）技术，成功制备了尺寸为150mm×100mm的TiAl基合金薄板，并利用光学显微镜（OM）、扫描电子显微镜（SEM）和x射线衍射（XRD）等测试手段，对真空退火或热压前后试样的显微形貌、物相组成等进行了分析。结果表明，蒸镀态TiAl基合金薄板由 γ相、α2相和ι相组成，成分呈梯度变化，内部自然分层，显微组织结构为柱状晶；经1000℃，16h的真空退火处理后，柱状晶和τ相消失，α2相含量显著减少，成分趋于均匀化；而经1250℃，1h的真空热压处理后，材料致密度得到明显提高。TiAl基合金薄板经真空退火或热压处理前后，断裂方式由沿晶断裂转变为解理断裂和沿晶断裂的混合断裂方式。
2007, 36(6):977-980.
Abstract:
采用低碳钢作为外包套材料，通过原位法粉末装管工艺（in-situPIT）制备出高密度Ti、zr掺杂的MgB2／Fe／Cu线材。将线材短样在氩气保护条件下，于650-800℃烧结2～5h。MgB2线材的微结构分析显示，通过该工艺制备的MgB2／Fe／Cu线材比MgB2块材具有更好的晶粒连结性和更高的致密度。采用标准的四引线法，在4．2K，0～8T的磁场下测试线材的I临界电流密度。测试结果显示，800℃烧结的Mg0.9Zr0.1B2／Fe／Cu线材获得了最高的临界电流密度。
采用低碳钢作为外包套材料，通过原位法粉末装管工艺（in-situPIT）制备出高密度Ti、zr掺杂的MgB2／Fe／Cu线材。将线材短样在氩气保护条件下，于650-800℃烧结2～5h。MgB2线材的微结构分析显示，通过该工艺制备的MgB2／Fe／Cu线材比MgB2块材具有更好的晶粒连结性和更高的致密度。采用标准的四引线法，在4．2K，0～8T的磁场下测试线材的I临界电流密度。测试结果显示，800℃烧结的Mg0.9Zr0.1B2／Fe／Cu线材获得了最高的临界电流密度。
2007, 36(6):981-984.
Abstract:
用固相反应法制备了（1-x）La2／3Ca1／3MnO3/xcr2O3（x为摩尔分数）复合样品，实验研究了在外加0～3T的磁场下，Cr203含量对该复合样品的电输运性质及磁电阻的影响。结果发现随着Cr2O3含量的增加，金属．绝缘体（M-I）转变温度耳急剧降低，并且当Cr2O3，含量x〉0．1时此转变消失。与此同时，电阻率随其含量增加而快速增大，特别的是在样品中观察到了较宽温度范围内显著增强了的磁电阻。这种结果的出现可能与Cr2O3有关的新相偏析在La2／3Ca1／3MnO3（LCMO）晶界和颗粒界面有关。
用固相反应法制备了（1-x）La2／3Ca1／3MnO3/xcr2O3（x为摩尔分数）复合样品，实验研究了在外加0～3T的磁场下，Cr203含量对该复合样品的电输运性质及磁电阻的影响。结果发现随着Cr2O3含量的增加，金属．绝缘体（M-I）转变温度耳急剧降低，并且当Cr2O3，含量x〉0．1时此转变消失。与此同时，电阻率随其含量增加而快速增大，特别的是在样品中观察到了较宽温度范围内显著增强了的磁电阻。这种结果的出现可能与Cr2O3有关的新相偏析在La2／3Ca1／3MnO3（LCMO）晶界和颗粒界面有关。
11 Study on Electronic Structure and Microdefects by Positron Annihilation Spectroscopy for NiTi Alloys
2007, 36(6):985-988.
Abstract:
Doppler-broading spectrum of positron annihilation radiation have been measured by using 2-detector coincidence technique for pure metals of Si, Ni, Ti and NiTi alloys with five different chemical compositions. The W parameters of NiTi alloys are calculated. The experimental results show that some 3d electrons are localized to form covalent bonds when Ni and Ti atoms aggregate to form NiTi alloy, decreasing the free electrons in metal bonds. The covalent bonds and metal bonds coexist in NiTi alloy. The Ni-49at%Ti alloy has the biggest W parameter, indicating that the quantity of defects is least in this component alloy. This may be the reason why the Ni-49at%Ti alloy has the best shape memory effect.
Doppler-broading spectrum of positron annihilation radiation have been measured by using 2-detector coincidence technique for pure metals of Si, Ni, Ti and NiTi alloys with five different chemical compositions. The W parameters of NiTi alloys are calculated. The experimental results show that some 3d electrons are localized to form covalent bonds when Ni and Ti atoms aggregate to form NiTi alloy, decreasing the free electrons in metal bonds. The covalent bonds and metal bonds coexist in NiTi alloy. The Ni-49at%Ti alloy has the biggest W parameter, indicating that the quantity of defects is least in this component alloy. This may be the reason why the Ni-49at%Ti alloy has the best shape memory effect.
2007, 36(6):989-993.
Abstract:
针对Ti-6Al-4V合金在加工和服役过程中的损伤特点,对Ti-6Al-4V合金锻件的3种典型误加工缺陷——槽缺陷、面缺陷和体缺陷进行了激光快速修复研究。激光修复区与锻件基体形成致密冶金结合,Al、V合金元素由锻件基体到激光修复区均匀分布,无宏观偏析。激光修复区组织为粗大原始β晶粒内分布细长的α针及编织细密的α+β板条组织,呈现典型的魏氏结构,热影响区组织从锻件的等轴α+转变β组织逐步过渡到魏氏(α+β)组织。对预制有3种类型缺陷的激光修复试样进行室温静载拉伸试验和硬度测试,结果表明修复试样的拉伸性能达到锻件标准(HB5224-1982)。激光修复试样的硬度和强度高于锻件基体,而塑性则低于锻件基体。因此,激光修复区和锻件基体可看作是一种“强+弱”的组合,这与二者的显微组织是相对应的。
针对Ti-6Al-4V合金在加工和服役过程中的损伤特点,对Ti-6Al-4V合金锻件的3种典型误加工缺陷——槽缺陷、面缺陷和体缺陷进行了激光快速修复研究。激光修复区与锻件基体形成致密冶金结合,Al、V合金元素由锻件基体到激光修复区均匀分布,无宏观偏析。激光修复区组织为粗大原始β晶粒内分布细长的α针及编织细密的α+β板条组织,呈现典型的魏氏结构,热影响区组织从锻件的等轴α+转变β组织逐步过渡到魏氏(α+β)组织。对预制有3种类型缺陷的激光修复试样进行室温静载拉伸试验和硬度测试,结果表明修复试样的拉伸性能达到锻件标准(HB5224-1982)。激光修复试样的硬度和强度高于锻件基体,而塑性则低于锻件基体。因此,激光修复区和锻件基体可看作是一种“强+弱”的组合,这与二者的显微组织是相对应的。
2007, 36(6):989-993.
Abstract:
针对Ti-6A1-4V合金在加工和服役过程中的损伤特点，对Ti-6A1-4V合金锻件的3种典型误加工缺陷——槽缺陷、面缺陷和体缺陷进行了激光快速修复研究。激光修复区与锻件基体形成致密冶金结合，Al、V合金元素由锻件基体到激光修复区均匀分布，无宏观偏析。激光修复区组织为粗大原始∥晶粒内分布细长的α针及编织细密的a＋β板条组织，呈现典型的魏氏结构，热影响区组织从锻件的等轴α＋转变β组织逐步过渡到魏氏（a＋β）组织。对预制有3种类型缺陷的激光修复试样进行室温静载拉伸试验和硬度测试，结果表明修复试样的拉伸性能达到锻件标准（HB5224-1982）。激光修复试样的硬度和强度高于锻件基体，而塑性则低于锻件基体。因此，激光修复区和锻件基体可看作是一种“强＋弱”的组合，这与二者的显微组织是相对应的。
针对Ti-6A1-4V合金在加工和服役过程中的损伤特点，对Ti-6A1-4V合金锻件的3种典型误加工缺陷——槽缺陷、面缺陷和体缺陷进行了激光快速修复研究。激光修复区与锻件基体形成致密冶金结合，Al、V合金元素由锻件基体到激光修复区均匀分布，无宏观偏析。激光修复区组织为粗大原始∥晶粒内分布细长的α针及编织细密的a＋β板条组织，呈现典型的魏氏结构，热影响区组织从锻件的等轴α＋转变β组织逐步过渡到魏氏（a＋β）组织。对预制有3种类型缺陷的激光修复试样进行室温静载拉伸试验和硬度测试，结果表明修复试样的拉伸性能达到锻件标准（HB5224-1982）。激光修复试样的硬度和强度高于锻件基体，而塑性则低于锻件基体。因此，激光修复区和锻件基体可看作是一种“强＋弱”的组合，这与二者的显微组织是相对应的。
2007, 36(6):994-997.
Abstract:
The static isothermal corrosions of Ti-50A1 and Ti-45A1-8Nb alloys in liquid zinc were studied and their positron lifetime spectrums were measured. The densities of free electrons of the bulk and microdefects in these alloys were calculated by using the positron lifetime parameters. It is found that the density of free electrons is lower in the bulk TiAl alloy than in Ti or Al matrix due to the localization and aggregation of some valence electrons in Ti and Al atoms to form TiAl alloy with a mixture bond of metallic bond and covalent bond. The large open defects occurs in the grain boundary of TiAl alloy and the bonding strength of grain boundary is weak due to the low density of free electrons. Then the densities of free electrons in the bulk and the grain boundary will simultaneously increase due to the great decrease of dissolution rate in liquid zinc as the TiAl alloy is alloyed with Nb
The static isothermal corrosions of Ti-50A1 and Ti-45A1-8Nb alloys in liquid zinc were studied and their positron lifetime spectrums were measured. The densities of free electrons of the bulk and microdefects in these alloys were calculated by using the positron lifetime parameters. It is found that the density of free electrons is lower in the bulk TiAl alloy than in Ti or Al matrix due to the localization and aggregation of some valence electrons in Ti and Al atoms to form TiAl alloy with a mixture bond of metallic bond and covalent bond. The large open defects occurs in the grain boundary of TiAl alloy and the bonding strength of grain boundary is weak due to the low density of free electrons. Then the densities of free electrons in the bulk and the grain boundary will simultaneously increase due to the great decrease of dissolution rate in liquid zinc as the TiAl alloy is alloyed with Nb
2007, 36(6):998-1001.
Abstract:
采用透射电镜和拉伸试验研究了温度对医用TiNi形状记忆合金（TiNiSMA）丝微观组织和力学性能的影响。结果表明，TiNiSMA微观组织和力学性能对温度变化极为敏感。对TiNiSMA进行短时加热处理，随加热温度升高，TiNiSMA组织由冷拔态纤维状组织逐渐转变为板条状马氏体群组织，且组织粗化，位错密度下降：TiNiSMA抗拉强度和超弹性能下降，塑性增加，当加热温度超过400℃时这种趋势更加显著。
采用透射电镜和拉伸试验研究了温度对医用TiNi形状记忆合金（TiNiSMA）丝微观组织和力学性能的影响。结果表明，TiNiSMA微观组织和力学性能对温度变化极为敏感。对TiNiSMA进行短时加热处理，随加热温度升高，TiNiSMA组织由冷拔态纤维状组织逐渐转变为板条状马氏体群组织，且组织粗化，位错密度下降：TiNiSMA抗拉强度和超弹性能下降，塑性增加，当加热温度超过400℃时这种趋势更加显著。
2007, 36(6):1002-1004.
Abstract:
选用0．15μm和5μm的Al2O3颗粒，采用挤压铸造法制备了体积分数为40％的铝基复合材料。利用选区电子衍射和高分辨电子显微技术研究了Al2O3P／1070Al界面附近基体的显微组织。结果表明，复合材料增强体颗粒为5μm时，基体存在大量的Eh热错配应力引发的位错，颗粒粒径为0．15μm时，基体表现为近无位错的组织特征，其缺陷形式为1～5nm的“微畸变区”，这主要是由于粒径小、分布弥散，微区应力均匀所致。
选用0．15μm和5μm的Al2O3颗粒，采用挤压铸造法制备了体积分数为40％的铝基复合材料。利用选区电子衍射和高分辨电子显微技术研究了Al2O3P／1070Al界面附近基体的显微组织。结果表明，复合材料增强体颗粒为5μm时，基体存在大量的Eh热错配应力引发的位错，颗粒粒径为0．15μm时，基体表现为近无位错的组织特征，其缺陷形式为1～5nm的“微畸变区”，这主要是由于粒径小、分布弥散，微区应力均匀所致。
2007, 36(6):1005-1007.
Abstract:
The effects of Mg element on the distribution of dislocations in Al-Cu-Mg alloy have been investigated. It has been shown that the interaction between Mg and Cu atoms was decreased since the concentration of Cu in Al matrix decreases due to the formation of Al2Cu precipitates during deformation and aging. The Mg element blocks the distributed glide of dislocations and thus inhibits the formation of cell structures due to the large atom radius, producing high aberrance energy and internal friction in Al matrix. Compared with the cell structures in typical metals and alloys with high stacking-fault energy, the dislocations in Al-Cu-Mg alloy are quasi-uniformly distributed and can decrease the free energy, named as the Taylor lattice distribution.
The effects of Mg element on the distribution of dislocations in Al-Cu-Mg alloy have been investigated. It has been shown that the interaction between Mg and Cu atoms was decreased since the concentration of Cu in Al matrix decreases due to the formation of Al2Cu precipitates during deformation and aging. The Mg element blocks the distributed glide of dislocations and thus inhibits the formation of cell structures due to the large atom radius, producing high aberrance energy and internal friction in Al matrix. Compared with the cell structures in typical metals and alloys with high stacking-fault energy, the dislocations in Al-Cu-Mg alloy are quasi-uniformly distributed and can decrease the free energy, named as the Taylor lattice distribution.
2007, 36(6):1008-1011.
Abstract:
A special furnace was designed and applied to produce an external electrical field up to 4 kV/cm and to study the wettability between copper and tungsten. The results showed that chromium can significantly reduce the wetting angle between copper and tungsten, so benefit to Cu-W infiltration system. The electrical field can also reduce the wetting angle, but not so stronger by comparing with chromium in the experimental electrical field range.
A special furnace was designed and applied to produce an external electrical field up to 4 kV/cm and to study the wettability between copper and tungsten. The results showed that chromium can significantly reduce the wetting angle between copper and tungsten, so benefit to Cu-W infiltration system. The electrical field can also reduce the wetting angle, but not so stronger by comparing with chromium in the experimental electrical field range.
2007, 36(6):1012-1015.
Abstract:
Tension-compression tests at high temperature were carried out on the specimens made of Ni based superalloys (DZ125 alloy) coated with bond coating (NiCoCrAlY) and zirconia ceramic coating by electron beam-physical vapor deposition(EB-PVD). Failure of the thermal barrier coatings (TBC) was investigated. The test results show that the failure of TBCs occurred from the initiation and expansion of fracture in TGO,differing from under thermal loading alone. There are two kinds of fracture cracks: initiating from the TGO/bond coat interface and the bond coat/diffusion coat,respectively,resulting in the failure of specimens at last. From the simulation results by finite element analysis (FE),it can be conclude that there are abrupt changes of stress state and value near the interfaces of TGO/TBC and TGO/bond coats. The abrupt change of radial stress would result in the failure of TBCs from the spallation of interface. The abrupt change of axial stress would accelerate the extension of the microcracks perpendicular to the interface,resulting in the rupture of specimens.
Tension-compression tests at high temperature were carried out on the specimens made of Ni based superalloys (DZ125 alloy) coated with bond coating (NiCoCrAlY) and zirconia ceramic coating by electron beam-physical vapor deposition(EB-PVD). Failure of the thermal barrier coatings (TBC) was investigated. The test results show that the failure of TBCs occurred from the initiation and expansion of fracture in TGO,differing from under thermal loading alone. There are two kinds of fracture cracks: initiating from the TGO/bond coat interface and the bond coat/diffusion coat,respectively,resulting in the failure of specimens at last. From the simulation results by finite element analysis (FE),it can be conclude that there are abrupt changes of stress state and value near the interfaces of TGO/TBC and TGO/bond coats. The abrupt change of radial stress would result in the failure of TBCs from the spallation of interface. The abrupt change of axial stress would accelerate the extension of the microcracks perpendicular to the interface,resulting in the rupture of specimens.
2007, 36(6):1016-1019.
Abstract:
采用有限元方法，对晶体结晶结束位置处的晶体内部热应力分布进行了数值模拟，结果表明：晶体在石英安瓿内壁附近，变径处以及头部尖端处的热应力较大，应力值约在10^8N／m^2数量级，晶体中部热应力分布较小且比较均匀，约为10^7N／m^2。为了防止晶体在生长过程中头部尖端处以及变径处的位错延伸至晶体内部，提出了在不同生长阶段采用不同下降速度，并且在晶体下降至变径处采用“回熔”操作的新工艺。实验结果表明：利用新工艺生长的晶体位错密度明显降低，约为2×10^2cm^-2，同时显著地提高了晶体的利用率。
采用有限元方法，对晶体结晶结束位置处的晶体内部热应力分布进行了数值模拟，结果表明：晶体在石英安瓿内壁附近，变径处以及头部尖端处的热应力较大，应力值约在10^8N／m^2数量级，晶体中部热应力分布较小且比较均匀，约为10^7N／m^2。为了防止晶体在生长过程中头部尖端处以及变径处的位错延伸至晶体内部，提出了在不同生长阶段采用不同下降速度，并且在晶体下降至变径处采用“回熔”操作的新工艺。实验结果表明：利用新工艺生长的晶体位错密度明显降低，约为2×10^2cm^-2，同时显著地提高了晶体的利用率。
2007, 36(6):1020-1023.
Abstract:
采用Gleeble-1500D热模拟机，通过对质量分数55％（Ti＋C）-45％Fe粉末压坯分别升温至250～800℃的解析实验，研究Fe-Ti-c体系在电场诱导下低温燃烧合成的显微组织演变。结果表明：在电场和大热流密度的共同作用下，体系的点火温度可大幅降低。当加热温度在250～350℃之间，体系虽未发生化学反应，但显微结构在一定程度随温度而发生变化；当加热温度在350-470℃范围内，体系被点燃发生“热爆”现象，而在燃烧合成反应前期，合成TiC的反应优先发生；当加热温度提高到470-670℃，合成TiC反应发生的同时还伴随有合成Fe2Ti的反应；然而随加热温度进一步提高到670-800℃，Fe2Ti会发生部分分解，进而使得合成TiC的反应继续进行。当温度达到800℃左右，该合成反应全部完成，产物由Fe、TiC和少量Fe2Ti组成。此外，通过合成反应所得呈圆球状、细小的TiC颗粒均匀地分布在Fe基体中，且随加热温度的提高而有所长大。
采用Gleeble-1500D热模拟机，通过对质量分数55％（Ti＋C）-45％Fe粉末压坯分别升温至250～800℃的解析实验，研究Fe-Ti-c体系在电场诱导下低温燃烧合成的显微组织演变。结果表明：在电场和大热流密度的共同作用下，体系的点火温度可大幅降低。当加热温度在250～350℃之间，体系虽未发生化学反应，但显微结构在一定程度随温度而发生变化；当加热温度在350-470℃范围内，体系被点燃发生“热爆”现象，而在燃烧合成反应前期，合成TiC的反应优先发生；当加热温度提高到470-670℃，合成TiC反应发生的同时还伴随有合成Fe2Ti的反应；然而随加热温度进一步提高到670-800℃，Fe2Ti会发生部分分解，进而使得合成TiC的反应继续进行。当温度达到800℃左右，该合成反应全部完成，产物由Fe、TiC和少量Fe2Ti组成。此外，通过合成反应所得呈圆球状、细小的TiC颗粒均匀地分布在Fe基体中，且随加热温度的提高而有所长大。
2007, 36(6):1024-1028.
Abstract:
研究了微量Ce、Ag对一种Al-Cu-Li合金热暴露后显微组织和性能的影响。Ce的添加提高T1相的抗粗化能力,有利于稳定合金热暴露后的力学性能;Ag的缺少降低了T1相的稳定性,使合金在150℃热暴露后的强度损失较大,但却使合金在200℃热暴露后保持较高的强度,这与不含Ag的合金在200℃热暴露时大量θ′相析出有关。
研究了微量Ce、Ag对一种Al-Cu-Li合金热暴露后显微组织和性能的影响。Ce的添加提高T1相的抗粗化能力,有利于稳定合金热暴露后的力学性能;Ag的缺少降低了T1相的稳定性,使合金在150℃热暴露后的强度损失较大,但却使合金在200℃热暴露后保持较高的强度,这与不含Ag的合金在200℃热暴露时大量θ′相析出有关。
2007, 36(6):1024-1028.
Abstract:
研究了微量Ce、Ag对一种Al-Cu-Li合金热暴露后显微组织和性能的影响。Ce的添加提高T1相的抗粗化能力，有利于稳定合金热暴露后的力学性能；Ag的缺少降低了乃相的稳定性，使合金在150℃热暴露后的强度损失较大，但却使合金在200℃热暴露后保持较高的强度，这与不含Ag的合金在200℃热暴露时大量θ相析出有关。
研究了微量Ce、Ag对一种Al-Cu-Li合金热暴露后显微组织和性能的影响。Ce的添加提高T1相的抗粗化能力，有利于稳定合金热暴露后的力学性能；Ag的缺少降低了乃相的稳定性，使合金在150℃热暴露后的强度损失较大，但却使合金在200℃热暴露后保持较高的强度，这与不含Ag的合金在200℃热暴露时大量θ相析出有关。
2007, 36(6):1029-1032.
Abstract:
铜基大块非晶合金Cu52.5Ti30Zr11.5Ni6与Cu53.1Ti31.4Zr9.5Ni6（at％）具有高的抗压缩断裂强度（σc,f），分别为2212MPa和2184MPa；断裂伸长率（εc,f）分别为2．1％和2．2％。断口微观形貌分析表明，Cu基大块非晶合金具有3种不同类型的微观形貌，分别与断口的3个断裂扩展区域相对应。由于断裂沿着2个不同方向进行，条带型脉状网络的产生，使得Cu基非晶具有高的抗压缩断裂强度。
铜基大块非晶合金Cu52.5Ti30Zr11.5Ni6与Cu53.1Ti31.4Zr9.5Ni6（at％）具有高的抗压缩断裂强度（σc,f），分别为2212MPa和2184MPa；断裂伸长率（εc,f）分别为2．1％和2．2％。断口微观形貌分析表明，Cu基大块非晶合金具有3种不同类型的微观形貌，分别与断口的3个断裂扩展区域相对应。由于断裂沿着2个不同方向进行，条带型脉状网络的产生，使得Cu基非晶具有高的抗压缩断裂强度。
2007, 36(6):1033-1036.
Abstract:
Amorphous and nanocrystalline Mg-based alloys (Mg65Cu25)100-xNdx (x=2,5,7,10) were prepared by melt-spinning. The microstructure of the as-quenched ribbons was characterized and the hydriding properties of these alloys were measured. The experiment results show that the as-quenched amorphous (Mg65Cu25)93Nd7 alloy display the best hydriding properties (hydriding kinetics and hydrogen absorption capacity),its maximum hydrogen capacity is 3.0 wt%H. The nanocrystalline (Mg65Cu25)98Nd2 alloy shows slower hydriding kinetics and lower hydrogen absorption capacity compared to the other Mg-Cu-Nd amorphous alloys. It is conformed that the glass-forming ability becomes strong with the increase of neodymium for the as-quenched (Mg65Cu25)100-xNdx alloys,which leads to the high H-capacity.
Amorphous and nanocrystalline Mg-based alloys (Mg65Cu25)100-xNdx (x=2,5,7,10) were prepared by melt-spinning. The microstructure of the as-quenched ribbons was characterized and the hydriding properties of these alloys were measured. The experiment results show that the as-quenched amorphous (Mg65Cu25)93Nd7 alloy display the best hydriding properties (hydriding kinetics and hydrogen absorption capacity),its maximum hydrogen capacity is 3.0 wt%H. The nanocrystalline (Mg65Cu25)98Nd2 alloy shows slower hydriding kinetics and lower hydrogen absorption capacity compared to the other Mg-Cu-Nd amorphous alloys. It is conformed that the glass-forming ability becomes strong with the increase of neodymium for the as-quenched (Mg65Cu25)100-xNdx alloys,which leads to the high H-capacity.
2007, 36(6):1037-1040.
Abstract:
Light-storing photocatalyst was prepared by combining long afterglow phosphor with TiO2 photocatalyst film, and bactericidal effect of this material on E.coli was investigated. TiOz shows high bactericidal ability under irradiation of light source and can decompose bacterial cell completely, but can not function in the darkness. The long afterglow phosphor can supply light for TiOz film after irradiation source is cut off, and hence E.coli can be killed by the light-storing photocatalyst even in the dark. This light-storing photocatalyst can be irradiated intermittently while maintaining photocatalyst activity all the time.
Light-storing photocatalyst was prepared by combining long afterglow phosphor with TiO2 photocatalyst film, and bactericidal effect of this material on E.coli was investigated. TiOz shows high bactericidal ability under irradiation of light source and can decompose bacterial cell completely, but can not function in the darkness. The long afterglow phosphor can supply light for TiOz film after irradiation source is cut off, and hence E.coli can be killed by the light-storing photocatalyst even in the dark. This light-storing photocatalyst can be irradiated intermittently while maintaining photocatalyst activity all the time.
2007, 36(6):1041-1045.
Abstract:
CuCr50 powders were first activated by mechanical alloying (MA),then used to prepare the contact materials by vacuum hot pressing. The results indicate that the CuCr50 powder by MA is ametastabe and supersaturated solid solution,would dissolve during the followed hot pressing. The microstructures and properties of bulk CuCr50 materials vary with the dissolving amounts of supersaturated solid solution. A bulk CuCr50 material of high density with fine and homogeneous Cr particles distributed can be acquired at lower temperature for shorter holding time in hot pressing due to the mechanically activated effect of MA powders. As a result,the synthetical properties of bulk CuCr50 materials fabricated by this method are superior to those prepared by other methods.
CuCr50 powders were first activated by mechanical alloying (MA),then used to prepare the contact materials by vacuum hot pressing. The results indicate that the CuCr50 powder by MA is ametastabe and supersaturated solid solution,would dissolve during the followed hot pressing. The microstructures and properties of bulk CuCr50 materials vary with the dissolving amounts of supersaturated solid solution. A bulk CuCr50 material of high density with fine and homogeneous Cr particles distributed can be acquired at lower temperature for shorter holding time in hot pressing due to the mechanically activated effect of MA powders. As a result,the synthetical properties of bulk CuCr50 materials fabricated by this method are superior to those prepared by other methods.
2007, 36(6):1046-1050.
Abstract:
用FeSO4、H3PO4、(NH4)2HPO4、NH3·H2O为原料合成NH4FePO4·H2O前驱体,再与LiCO3和蔗糖均匀混合,烘干后埋入活性炭粉中,在最大功率为800 W的家用微波炉中以320～640 W功率加热一定时间,获得LiFePO4.用扫描电镜和X射线衍射分析对NH4FePO4.H2O和LiFePO4的形貌结构进行了表征.研究了微波输入功率、加热时间对LiFePO4结构和电化学性能的影响.研究表明,在320 W下微波加热15 min得到的LiFePO4材料,具有良好的电化学性能.在0.05 C放电倍率下可达到156 mAh/g的放电比容量,在0.5 C放电倍率下仍可达到115 mAh/g的放电比容量.
用FeSO4、H3PO4、(NH4)2HPO4、NH3·H2O为原料合成NH4FePO4·H2O前驱体,再与LiCO3和蔗糖均匀混合,烘干后埋入活性炭粉中,在最大功率为800 W的家用微波炉中以320～640 W功率加热一定时间,获得LiFePO4.用扫描电镜和X射线衍射分析对NH4FePO4.H2O和LiFePO4的形貌结构进行了表征.研究了微波输入功率、加热时间对LiFePO4结构和电化学性能的影响.研究表明,在320 W下微波加热15 min得到的LiFePO4材料,具有良好的电化学性能.在0.05 C放电倍率下可达到156 mAh/g的放电比容量,在0.5 C放电倍率下仍可达到115 mAh/g的放电比容量.
2007, 36(6):1051-1054.
Abstract:
研究了镁离子在金属-电介质复合材料中的改性作用。通过SEM、EDS、XRD等分析手段综合得出Mg^2＋取代了BaTiO3晶格中B位的Ti^4＋，并使置换出来的Ti^4＋在样品表面形成富集。介电性能分析证明Mg^2＋可以明显降低系统介电损耗，展宽并压低居里峰。当Mg^2＋添加量为0．9％（摩尔分数），系统介电常数高达11395，介电损耗为0．006，并在-55～150℃范围内容量变化率〈±10％。
研究了镁离子在金属-电介质复合材料中的改性作用。通过SEM、EDS、XRD等分析手段综合得出Mg^2＋取代了BaTiO3晶格中B位的Ti^4＋，并使置换出来的Ti^4＋在样品表面形成富集。介电性能分析证明Mg^2＋可以明显降低系统介电损耗，展宽并压低居里峰。当Mg^2＋添加量为0．9％（摩尔分数），系统介电常数高达11395，介电损耗为0．006，并在-55～150℃范围内容量变化率〈±10％。
2007, 36(6):1055-1057.
Abstract:
Gold nanoparticles are prepared in O/W microemulsion of SDS/Vc/H2O (0.001 mol?L-1 HAuCl4) system by using Vc as the reducing agent. The size of obtained polygonal gold nanoparticles is from 5 nm to 20 nm,and increases with the content increase of HAuCl4 in O/W microemulsion in the condition of SDS/Vc weight ratio of 50/50. The formation mechanism of gold nanoparticles is discussed in the present paper.
Gold nanoparticles are prepared in O/W microemulsion of SDS/Vc/H2O (0.001 mol?L-1 HAuCl4) system by using Vc as the reducing agent. The size of obtained polygonal gold nanoparticles is from 5 nm to 20 nm,and increases with the content increase of HAuCl4 in O/W microemulsion in the condition of SDS/Vc weight ratio of 50/50. The formation mechanism of gold nanoparticles is discussed in the present paper.
31 Effects of Substitution of A! for Ni on Properties of A2B7-Type Hydrogen Storage Electrode Alloys
2007, 36(6):1058-1062.
Abstract:
The La0.7Mg0.3(Ni0.85-xCo0.15Alx)3.4 hydrogen storage electrode alloys were prepared by cold crucible melting under argon gas atmosphere. The phase structure of these alloys and the electrochemical properties and surface of corresponding electrodes were investigated by means of XRD and tri-electrode test system and SEM. Rietveld analyses show that all these alloys consist of hexagonal Ce2Ni7-type main-phase,hexagonal CaCu5-type phase,rhombohedral PuNi3-type phase,cubic MgCu2-type Laves-phase and orthorhombic BCr-type phase. The Ce2Ni7-type main-phase content and the cell volume of all these phases increase with increasing of x. P-C isotherms show that hydrogen-desorption plateau region narrows,and the plateau pressure decreases and the plateau becomes steeper with increasing of x. The electrochemical results show that maximum discharge capacity and high-rate dischargeability decrease,cyclic stability is improved markedly with increasing of x.
The La0.7Mg0.3(Ni0.85-xCo0.15Alx)3.4 hydrogen storage electrode alloys were prepared by cold crucible melting under argon gas atmosphere. The phase structure of these alloys and the electrochemical properties and surface of corresponding electrodes were investigated by means of XRD and tri-electrode test system and SEM. Rietveld analyses show that all these alloys consist of hexagonal Ce2Ni7-type main-phase,hexagonal CaCu5-type phase,rhombohedral PuNi3-type phase,cubic MgCu2-type Laves-phase and orthorhombic BCr-type phase. The Ce2Ni7-type main-phase content and the cell volume of all these phases increase with increasing of x. P-C isotherms show that hydrogen-desorption plateau region narrows,and the plateau pressure decreases and the plateau becomes steeper with increasing of x. The electrochemical results show that maximum discharge capacity and high-rate dischargeability decrease,cyclic stability is improved markedly with increasing of x.
2007, 36(6):1063-1065.
Abstract:
用正交实验考察了溶液温度、pH值、搅拌速度等因素对催化剂吸附量的影响规律，并据此用浸渍及甲醛还原法制备了系列Ru／C催化剂，在0．5MPa、120℃下测得葡萄糖加氢生成山梨醇的催化活性、山梨醇选择性和催化剂的稳定性。并运用程序升温还原TPR（temperatureprogrammedreduction）技术研究了催化剂的表面还原性质。结果表明：钌的负载量对Ru／C催化剂的性能影响较大，钌负载量为5％时，制得的催化剂具有较佳的各项性能。钌的负载量越少时，负载钌的分散度越高，钌与载体间作用力越强，催化剂的还原温度越高。同时，随着含钌量的增加，催化剂的还原峰发生明显的变化，负载量为5％时出现了明显的肩峰，化学吸附是催化活性的主要来源。
用正交实验考察了溶液温度、pH值、搅拌速度等因素对催化剂吸附量的影响规律，并据此用浸渍及甲醛还原法制备了系列Ru／C催化剂，在0．5MPa、120℃下测得葡萄糖加氢生成山梨醇的催化活性、山梨醇选择性和催化剂的稳定性。并运用程序升温还原TPR（temperatureprogrammedreduction）技术研究了催化剂的表面还原性质。结果表明：钌的负载量对Ru／C催化剂的性能影响较大，钌负载量为5％时，制得的催化剂具有较佳的各项性能。钌的负载量越少时，负载钌的分散度越高，钌与载体间作用力越强，催化剂的还原温度越高。同时，随着含钌量的增加，催化剂的还原峰发生明显的变化，负载量为5％时出现了明显的肩峰，化学吸附是催化活性的主要来源。
2007, 36(6):1066-1069.
Abstract:
The electrochemical properties of Nd2Fe14B single crystal grain,conventional sintered NdFeB and SPS NdFeB in electrolyte were studied. The microstructures and compositions of the magnets were investigated with scanning electron microscope (SEM) and energy dispersive X-ray detector (EDX). Polarization curves in 3.5% NaCl solution show that Nd2Fe14B single crystal grain has displayed most positive corrosion potential and the SPS NdFeB magnet has more noble potentials compared with the conventional sintered one. Compared with conventional sintered NdFeB magnet,SPS processed magnet has original microstructure i.e. the grain size of the Nd2Fe14B main phase is fine and uniform,and the fine Nd-rich phase does not form along the grain boundaries of main phase,but agglomerates into the triple junctions. The pathways for corrosion propagation are restricted and the inter-granular corrosion process though Nd-rich phase in the magnet is suppressed effectively. Therefore,the SPS NdFeB magnet possesses excellent corrosion resistance. Autoclaves test indicates that a strong correlation has been established between an increase in the total rare earth level,which corresponds to the amount of Nd-rich phase,and an increase in the corrosion rate. The results show that chemical character; microstructure and the amount of Nd-rich phase determine the corrosion resistance of magnets and indicate an intergranular corrosion leads to poor corrosion resistance.
The electrochemical properties of Nd2Fe14B single crystal grain,conventional sintered NdFeB and SPS NdFeB in electrolyte were studied. The microstructures and compositions of the magnets were investigated with scanning electron microscope (SEM) and energy dispersive X-ray detector (EDX). Polarization curves in 3.5% NaCl solution show that Nd2Fe14B single crystal grain has displayed most positive corrosion potential and the SPS NdFeB magnet has more noble potentials compared with the conventional sintered one. Compared with conventional sintered NdFeB magnet,SPS processed magnet has original microstructure i.e. the grain size of the Nd2Fe14B main phase is fine and uniform,and the fine Nd-rich phase does not form along the grain boundaries of main phase,but agglomerates into the triple junctions. The pathways for corrosion propagation are restricted and the inter-granular corrosion process though Nd-rich phase in the magnet is suppressed effectively. Therefore,the SPS NdFeB magnet possesses excellent corrosion resistance. Autoclaves test indicates that a strong correlation has been established between an increase in the total rare earth level,which corresponds to the amount of Nd-rich phase,and an increase in the corrosion rate. The results show that chemical character; microstructure and the amount of Nd-rich phase determine the corrosion resistance of magnets and indicate an intergranular corrosion leads to poor corrosion resistance.
2007, 36(6):1070-1073.
Abstract:
研究了一种新型的制备金属藕状多孔结构技术——选区激光烧结，着重说明该技术的基本原理和工艺过程，并利用此制备技术成功获得了藕状多孔试样。利用SEM分析了316不锈钢藕状多孔试样的微观孔隙特征，并测定其孔隙率，结果表明其孔径大小分布均匀（2-4μm），平均孔隙率约为60％，孔隙贯通性良好；初步探讨了选区激光烧结制备316不锈钢藕状多孔结构的成形机制。
研究了一种新型的制备金属藕状多孔结构技术——选区激光烧结，着重说明该技术的基本原理和工艺过程，并利用此制备技术成功获得了藕状多孔试样。利用SEM分析了316不锈钢藕状多孔试样的微观孔隙特征，并测定其孔隙率，结果表明其孔径大小分布均匀（2-4μm），平均孔隙率约为60％，孔隙贯通性良好；初步探讨了选区激光烧结制备316不锈钢藕状多孔结构的成形机制。
Hu Tao
,
Chu Chenglin
,
Sun Weibin
,
Wang Juan
,
Zhou Jingyan
,
Dong Yinsheng
,
Pu Yaopu
,
Lin Pinghua
,
Paul K Chu
2007, 36(6):1074-1077.
Abstract:
通过高级氧化法对NiTi形状记忆合金进行表面改性，SEM和TF—XRD分析证实，羟自由基（·OH）氧化后的NiTi形状记忆合金表面生成了金红石和锐钛矿结构的二氧化钛薄膜。通过测定动态凝血时间、溶血率和研究血小板黏附行为等方法进行了血液相容性评估。结果表明，经高级氧化法表面改性后的NiTi形状记忆合金血液相容性获得了明显的改善。
通过高级氧化法对NiTi形状记忆合金进行表面改性，SEM和TF—XRD分析证实，羟自由基（·OH）氧化后的NiTi形状记忆合金表面生成了金红石和锐钛矿结构的二氧化钛薄膜。通过测定动态凝血时间、溶血率和研究血小板黏附行为等方法进行了血液相容性评估。结果表明，经高级氧化法表面改性后的NiTi形状记忆合金血液相容性获得了明显的改善。
2007, 36(6):1078-1081.
Abstract:
A new Y6Fe60.5Co11.5B22 Fe-based bulk metallic glass with a maximum diameter of 2 mm has been fabricated by suction casting method in a water-cooled copper mould. The interrelationship between cooling rates and magnetic properties were investigated and the critical cooling rate of the amorphous alloy was calculated. The bulk amorphous alloy has a coercivity of 2.53 A/m,a saturated magnetization of 1.24 T,and a high initial susceptibility. The critical cooling rate (Rc) of the Y6Fe60.5Co11.5B22 amorphous alloy was determined to be about 119 K/s.
A new Y6Fe60.5Co11.5B22 Fe-based bulk metallic glass with a maximum diameter of 2 mm has been fabricated by suction casting method in a water-cooled copper mould. The interrelationship between cooling rates and magnetic properties were investigated and the critical cooling rate of the amorphous alloy was calculated. The bulk amorphous alloy has a coercivity of 2.53 A/m,a saturated magnetization of 1.24 T,and a high initial susceptibility. The critical cooling rate (Rc) of the Y6Fe60.5Co11.5B22 amorphous alloy was determined to be about 119 K/s.
2007, 36(6):1082-1084.
Abstract:
The microstructure and phase composition of Sm-Fe alloy during quenching process were investigated by means of SEM, XRD, EDX, and AFM, etc. It is indicated that the Sm-Fe alloy cast consists of Sm2Fe17 phase, Sm-rich phase and a mount of a-Fe phase, and the alloy of single Sm2Fel7-phase was obtained after homogenization annealing. The alloy is composed of the Sm2Fe17 phase with Th2Zn17-type structure and a few a-Fe phase, with unhomogeneous grain sizes of about 100 nm when the quenching velocity is 10 m/s. But at 20 m/s, the alloy still contains Sm2Fe17 and a-Fe phases, but the content of a-Fe is increased when compared with at 10 m/s. At the same time, the stable Sm2Fe17 phase starts to convert into sub-stable SmloFe90 phase. At 30 m/s, the alloy is completely composed of SmloFe90 phase with the ThCuT-type structure and homogeneous grain size of40-50 nm.
The microstructure and phase composition of Sm-Fe alloy during quenching process were investigated by means of SEM, XRD, EDX, and AFM, etc. It is indicated that the Sm-Fe alloy cast consists of Sm2Fe17 phase, Sm-rich phase and a mount of a-Fe phase, and the alloy of single Sm2Fel7-phase was obtained after homogenization annealing. The alloy is composed of the Sm2Fe17 phase with Th2Zn17-type structure and a few a-Fe phase, with unhomogeneous grain sizes of about 100 nm when the quenching velocity is 10 m/s. But at 20 m/s, the alloy still contains Sm2Fe17 and a-Fe phases, but the content of a-Fe is increased when compared with at 10 m/s. At the same time, the stable Sm2Fe17 phase starts to convert into sub-stable SmloFe90 phase. At 30 m/s, the alloy is completely composed of SmloFe90 phase with the ThCuT-type structure and homogeneous grain size of40-50 nm.
2007, 36(6):1085-1087.
Abstract:
利用微弧氧化技术，以NaOH为电解液，对Zr-Nb合金进行表面处理，以改善其抗溶液腐蚀性能。利用SEM观察到Zr-Nb合金微弧氧化膜厚约8μm，膜层为一连续整体，厚度均匀，与基体结合牢固。X射线衍射分析表明，微弧氧化膜主要由四方和单斜相的二氧化锆组成。通过电化学极化曲线测量，对Zr-Nb合金微弧氧化膜的抗腐蚀性能进行了评价，结果表明，氧化膜抗腐蚀性能比基体提高显著。
利用微弧氧化技术，以NaOH为电解液，对Zr-Nb合金进行表面处理，以改善其抗溶液腐蚀性能。利用SEM观察到Zr-Nb合金微弧氧化膜厚约8μm，膜层为一连续整体，厚度均匀，与基体结合牢固。X射线衍射分析表明，微弧氧化膜主要由四方和单斜相的二氧化锆组成。通过电化学极化曲线测量，对Zr-Nb合金微弧氧化膜的抗腐蚀性能进行了评价，结果表明，氧化膜抗腐蚀性能比基体提高显著。
39 Effects of Metal Hydrides Addition on the Strength and Microstructure of Nd-Fe-B Sintered Magnets
2007, 36(6):1088-1090.
Abstract:
The effects of PrHx addition on the magnetic properties, microstructure and bending strength have been studied for the sintered Nd-Fe-B magnets. It shows that the bending strength and coercivity can be effectively improved and enhanced by the addition of PrHx for the experimental magnets. The magnets have the optimal microstructure according to SEM images, and the atoms diffusion can be potentially improved among the magnetic main phase Nd2Fel4B after the PrHx addition.
The effects of PrHx addition on the magnetic properties, microstructure and bending strength have been studied for the sintered Nd-Fe-B magnets. It shows that the bending strength and coercivity can be effectively improved and enhanced by the addition of PrHx for the experimental magnets. The magnets have the optimal microstructure according to SEM images, and the atoms diffusion can be potentially improved among the magnetic main phase Nd2Fel4B after the PrHx addition.
2007, 36(6):1091-1094.
Abstract:
采用机械合金化（MA）工艺，以W-25％CuO为原料，球磨参数设置为：球料比20：1、球磨转速500r／min，球磨时间范围1-40h，采用球磨20min、空气冷却30min的循环球磨方式。对不同球磨时间条件下制备的粉末进行了x射线衍射和透射电镜分析。结果表明，通过MA工艺可在较短时间内（lh）获得W-Cu纳米晶粉末，球磨时粉体中的CuO发生了还原，部分W被氧化成WOx（x=2～3），球磨后w粉的平均晶粒尺寸为12．5nm左右，最小晶粒5～6nm；W粉颗粒的最终形态为球形，并被Cu所包覆。
采用机械合金化（MA）工艺，以W-25％CuO为原料，球磨参数设置为：球料比20：1、球磨转速500r／min，球磨时间范围1-40h，采用球磨20min、空气冷却30min的循环球磨方式。对不同球磨时间条件下制备的粉末进行了x射线衍射和透射电镜分析。结果表明，通过MA工艺可在较短时间内（lh）获得W-Cu纳米晶粉末，球磨时粉体中的CuO发生了还原，部分W被氧化成WOx（x=2～3），球磨后w粉的平均晶粒尺寸为12．5nm左右，最小晶粒5～6nm；W粉颗粒的最终形态为球形，并被Cu所包覆。
2007, 36(6):1095-1098.
Abstract:
以sn-Pd胶体溶液为活化剂，对空心微球的表面进行活化，并采用化学镀工艺，在其表面分别镀Co和Co-Fe薄膜。利用扫描电子显微镜（SEM）、能量散射谱（EDS）和x-射线衍射仪（XRD）分别对镀膜前后的空心微球进行表征，用网络矢量分析仪测试镀膜后空心微球的电磁损耗和微波吸收性能。结果表明：经过活化后的空心微球表面分别淀积了均匀、致密的Co和Co-Fe薄膜。改性后的空心微球在2-18GHz的频率范围内对电磁波有不同程度的吸收，具有宽频的吸收特性。
以sn-Pd胶体溶液为活化剂，对空心微球的表面进行活化，并采用化学镀工艺，在其表面分别镀Co和Co-Fe薄膜。利用扫描电子显微镜（SEM）、能量散射谱（EDS）和x-射线衍射仪（XRD）分别对镀膜前后的空心微球进行表征，用网络矢量分析仪测试镀膜后空心微球的电磁损耗和微波吸收性能。结果表明：经过活化后的空心微球表面分别淀积了均匀、致密的Co和Co-Fe薄膜。改性后的空心微球在2-18GHz的频率范围内对电磁波有不同程度的吸收，具有宽频的吸收特性。
2007, 36(6):1099-1101.
Abstract:
The extraction of Pr3+was studied by using heptane containing bis(2-ethylhexyl)phosphinic acid in sodium perchlorate,chloroacetic acid and citric acid medium,respectively. The effects of extraction equilibrium time,different mediums,PIA-8 concentrations upon extraction Pr3+ and that of concentration of back extraction agent on back extraction rate of Pr3+ were discussed. The composition of the extracted compound was shown to be La(HA2)3.The pH1/2 values of La3+,Ce3+,Pr3+,Nd3+,Sm3+ and Eu3+ in different mediums were determined,it is 3.69,3.30,3.16,3.10,2.68 and 2.54 in sodium perchlorate medium respectively,3.65,3.27,3.12,3.08,2.66 and 2.50 in chloroacetic acid mediums,respectively,4.34,4.26,4.11,3.91,3.57 and 3.38 in citric acid mediums,respectively.
The extraction of Pr3+was studied by using heptane containing bis(2-ethylhexyl)phosphinic acid in sodium perchlorate,chloroacetic acid and citric acid medium,respectively. The effects of extraction equilibrium time,different mediums,PIA-8 concentrations upon extraction Pr3+ and that of concentration of back extraction agent on back extraction rate of Pr3+ were discussed. The composition of the extracted compound was shown to be La(HA2)3.The pH1/2 values of La3+,Ce3+,Pr3+,Nd3+,Sm3+ and Eu3+ in different mediums were determined,it is 3.69,3.30,3.16,3.10,2.68 and 2.54 in sodium perchlorate medium respectively,3.65,3.27,3.12,3.08,2.66 and 2.50 in chloroacetic acid mediums,respectively,4.34,4.26,4.11,3.91,3.57 and 3.38 in citric acid mediums,respectively.
2007, 36(6):1102-1105.
Abstract:
The vitro blood anticoagulant activities,including rothrombin time (PT),plasma recalcification time (RT) and kinetic cloting time,were measured and compared for pure magnesium,magnesium alloys and a comparison material (316L stainless steel). The pure magnesium rods were implanted into the back muscle of rats to evaluate the osteo-induction.The results showed that the blood anticoagulant activities were in the order of Mg
The vitro blood anticoagulant activities,including rothrombin time (PT),plasma recalcification time (RT) and kinetic cloting time,were measured and compared for pure magnesium,magnesium alloys and a comparison material (316L stainless steel). The pure magnesium rods were implanted into the back muscle of rats to evaluate the osteo-induction.The results showed that the blood anticoagulant activities were in the order of Mg
2007, 36(6):1106-1109.
Abstract:
为了解杂质气体对钯柱氢氘排代性能的影响程度，利用快排代法考察了排代氢中添加CO，O2，CH4，CO2等气体后室温下钯柱氢氘排代效率的变化情况，并测量了钯表面O2，CO，CH4的等温吸附曲线。结果表明：H2中仅加入10μL／L的CO，排代性能已显著下降，随CO含量的增加，排代性能随之显著降低，当CO含量增至3000μL／L时将几乎没有排代效果；O2的影响比CO弱，H2中含3000μL/L的O2时排代性能约下降20％；然而当H2中含3000μL／L的CO2时排代性能约下降3．2％；CH4的影响则相对可忽略。
为了解杂质气体对钯柱氢氘排代性能的影响程度，利用快排代法考察了排代氢中添加CO，O2，CH4，CO2等气体后室温下钯柱氢氘排代效率的变化情况，并测量了钯表面O2，CO，CH4的等温吸附曲线。结果表明：H2中仅加入10μL／L的CO，排代性能已显著下降，随CO含量的增加，排代性能随之显著降低，当CO含量增至3000μL／L时将几乎没有排代效果；O2的影响比CO弱，H2中含3000μL/L的O2时排代性能约下降20％；然而当H2中含3000μL／L的CO2时排代性能约下降3．2％；CH4的影响则相对可忽略。
2007, 36(6):1110-1114.
Abstract:
Electrochemical capacitor (ECs) is one of the novel energy-storage and conversion devices,by which the electric energy can be obtained from the electrochemical double-layer or the redox reaction occurring on the interface between electrode and electrolyte with the advantages of large power density,large energy density,excellent reversibility and long cycle life. In the present paper,the recent application progresses and developments of the composite electrode materials for ECs have been reviewed and introduced in detail.
Electrochemical capacitor (ECs) is one of the novel energy-storage and conversion devices,by which the electric energy can be obtained from the electrochemical double-layer or the redox reaction occurring on the interface between electrode and electrolyte with the advantages of large power density,large energy density,excellent reversibility and long cycle life. In the present paper,the recent application progresses and developments of the composite electrode materials for ECs have been reviewed and introduced in detail.
2007, 36(6):1115-1118.
Abstract:
The effect factors, micro measurements and numerical simulation were reviewed and discussed for the interracial strength of SiC fiber reinforced titanium composites. Special attentions were paid to the limitation of the experimental measuring numerical modeling. The way of quantitative study on the interracial bonding strength was pointed out for the composites
The effect factors, micro measurements and numerical simulation were reviewed and discussed for the interracial strength of SiC fiber reinforced titanium composites. Special attentions were paid to the limitation of the experimental measuring numerical modeling. The way of quantitative study on the interracial bonding strength was pointed out for the composites
2007, 36(6):1119-1123.
Abstract:
Nanotechnology can remarkably modify the hydrogen storage properties of hydrogen storage materials. The latest progresses on the nanotechnological aspects of hydrogen storage materials are described and discussed in this paper. Some problems to be overcome are pointed out, and some suggestions for future work are given.
Nanotechnology can remarkably modify the hydrogen storage properties of hydrogen storage materials. The latest progresses on the nanotechnological aspects of hydrogen storage materials are described and discussed in this paper. Some problems to be overcome are pointed out, and some suggestions for future work are given.
2007, 36(6):1124-1128.
Abstract:
The changes of A and B elements have great effects on the electrochemical properties and microstructure for the rare-earth based ABs-type hydrogen storage alloy as the cathode material of Ni-MH batteries. The electrochemical properties of rare earth-based hydrogen storage alloy, and the substitution of A and B in the ABs-type hydrogen storage alloy are reviewed and the relationship of substituted elements and electrochemical properties are summarized in order to provide some ideas for researchers.
The changes of A and B elements have great effects on the electrochemical properties and microstructure for the rare-earth based ABs-type hydrogen storage alloy as the cathode material of Ni-MH batteries. The electrochemical properties of rare earth-based hydrogen storage alloy, and the substitution of A and B in the ABs-type hydrogen storage alloy are reviewed and the relationship of substituted elements and electrochemical properties are summarized in order to provide some ideas for researchers.
