Volume 35,Issue 6,2006 Table of Contents
2006, 35(6):841-844.
Abstract:
钨合金与贫铀弹相比,在穿甲过程中由于形成“蘑菇头”而不能形成很好的绝热剪切带而使其穿甲性能不及贫铀弹.钨合金在高速冲击加载下的动态力学性能和失效决定着钨合金穿甲性能,为此,本文综述了十多年来国内外对钨合金在高速冲击加载下的动态力学性能和失效机理的研究现状.
钨合金与贫铀弹相比,在穿甲过程中由于形成“蘑菇头”而不能形成很好的绝热剪切带而使其穿甲性能不及贫铀弹.钨合金在高速冲击加载下的动态力学性能和失效决定着钨合金穿甲性能,为此,本文综述了十多年来国内外对钨合金在高速冲击加载下的动态力学性能和失效机理的研究现状.
Hu Rui
,
Zhang Huangli
,
Geng Xinguo
,
Li Jinshan
,
Fu Hengzhi
,
Feng Yong
,
Zhang Pingxiang
,
Zhou Lian
2006, 35(6):845-849.
Abstract:
Large bulk HTS single crystal can be used to measure accurately the structure and understand the relation between crystal structure and properties, as well as to obtain more information on its nature for high Tc superconductor. It is important to understand and explain the mechanism of high Tc superconductivity and their applications. It is quite difficult to obtain a large bulk HTS single crystal due to peritectic reaction, peritectic transformation and incoordinate composition transformation in the crystal growth process of HTS oxides, especially, a liquid-solid line of steep slope in YBCO phase diagram. Crystal growth theory related to HTS single crystal grown and techniques, some effects and improvements for crystal growth were discussed in this paper. In addition, some techniques for preparing HTS single crystal were summarized.
Large bulk HTS single crystal can be used to measure accurately the structure and understand the relation between crystal structure and properties, as well as to obtain more information on its nature for high Tc superconductor. It is important to understand and explain the mechanism of high Tc superconductivity and their applications. It is quite difficult to obtain a large bulk HTS single crystal due to peritectic reaction, peritectic transformation and incoordinate composition transformation in the crystal growth process of HTS oxides, especially, a liquid-solid line of steep slope in YBCO phase diagram. Crystal growth theory related to HTS single crystal grown and techniques, some effects and improvements for crystal growth were discussed in this paper. In addition, some techniques for preparing HTS single crystal were summarized.
2006, 35(6):850-854.
Abstract:
Recent developments on laser cladding of titanium and its alloys are reviewed. The research progresses on the clad layer with enhanced wear resistance, the improved biocompatibility, the composite clad layer, the functionally gradient clad layers and the laser rapid forming process of titanium alloys are summarized. Some problems to be solved are suggested for the study of laser cladding on titanium alloys.
Recent developments on laser cladding of titanium and its alloys are reviewed. The research progresses on the clad layer with enhanced wear resistance, the improved biocompatibility, the composite clad layer, the functionally gradient clad layers and the laser rapid forming process of titanium alloys are summarized. Some problems to be solved are suggested for the study of laser cladding on titanium alloys.
2006, 35(6):855-859.
Abstract:
在TiAl基合金相空间与相界面价电子结构计算的基础上,利用表征相结构单元成键能力的相结构因子F与表征界面结合强度的界面结合因子△ρ给出了一种计算TiAl基合金屈服强度的方法.该方法以实验数据为基础,进行回归分析求α2相体积分数,以理论屈服强度与实际屈服强度之差是否满足一级近似作为合金基体γ相强度σs^γ-TiAl取值的判据,用相结构单元最强键上的共用电子对数nA计算Nb在γ相与α2相中的含量Wγ^Nb和Wα2^Nb.计算了全片层TiAl,TiAl-8Nb,TiAl-10Nb合金的屈服强度,与实测值比较,理论计算结果令人满意.
在TiAl基合金相空间与相界面价电子结构计算的基础上,利用表征相结构单元成键能力的相结构因子F与表征界面结合强度的界面结合因子△ρ给出了一种计算TiAl基合金屈服强度的方法.该方法以实验数据为基础,进行回归分析求α2相体积分数,以理论屈服强度与实际屈服强度之差是否满足一级近似作为合金基体γ相强度σs^γ-TiAl取值的判据,用相结构单元最强键上的共用电子对数nA计算Nb在γ相与α2相中的含量Wγ^Nb和Wα2^Nb.计算了全片层TiAl,TiAl-8Nb,TiAl-10Nb合金的屈服强度,与实测值比较,理论计算结果令人满意.
2006, 35(6):860-865.
Abstract:
为了研究碳离子注入对纯锆耐蚀性的影响,用MEVVA源对纯锆样品进行了1×1016ions/cm2至1×1017ions/cm2的碳离子注入,注入加速电压为40 kV.用X射线光电子能谱(XPS)和俄歇电子谱(AES)分析了注入样品表层元素的价态和深度分布.透射电镜(TEM)用来观察碳离子注入样品的微观结构;碳离子注入样品后相结构的变化用掠角X射线衍射(GAXRD)来检测.纯锆注入样品随后浸入1 mol/L的硫酸溶液中,测其极化曲线以评价其耐蚀性.发现碳离子注入极大地提高了纯锆基体的耐蚀行为,剂量越高,耐蚀性越好.最后,对碳离子注入导致纯锆基体腐蚀行为发生改变的机理进行了讨论.
为了研究碳离子注入对纯锆耐蚀性的影响,用MEVVA源对纯锆样品进行了1×1016ions/cm2至1×1017ions/cm2的碳离子注入,注入加速电压为40 kV.用X射线光电子能谱(XPS)和俄歇电子谱(AES)分析了注入样品表层元素的价态和深度分布.透射电镜(TEM)用来观察碳离子注入样品的微观结构;碳离子注入样品后相结构的变化用掠角X射线衍射(GAXRD)来检测.纯锆注入样品随后浸入1 mol/L的硫酸溶液中,测其极化曲线以评价其耐蚀性.发现碳离子注入极大地提高了纯锆基体的耐蚀行为,剂量越高,耐蚀性越好.最后,对碳离子注入导致纯锆基体腐蚀行为发生改变的机理进行了讨论.
2006, 35(6):866-870.
Abstract:
研究了紧耦合气雾化制粉过程中AlNiY合金熔滴的冷却行为以及非晶颗粒的形成机制.结果表明：（1）AlNiY合金非晶化的临界冷却速率大致为10^3K/s;（2）熔滴的冷却速率与直径成反比,当直径小于25 μm时,熔滴达到临界冷却速率实现非晶化.当直径大于25μm时,熔滴无法获得非晶化临界冷却速率,只能发生形核结晶;（3）熔滴的非晶化还与雾化过程相关,由于熔滴破碎时的位置和温度不同,获得的冷却速率将不同,出现了相同直径（小于25 μm）的颗粒存在非晶和结晶两种状态.
研究了紧耦合气雾化制粉过程中AlNiY合金熔滴的冷却行为以及非晶颗粒的形成机制.结果表明：（1）AlNiY合金非晶化的临界冷却速率大致为10^3K/s;（2）熔滴的冷却速率与直径成反比,当直径小于25 μm时,熔滴达到临界冷却速率实现非晶化.当直径大于25μm时,熔滴无法获得非晶化临界冷却速率,只能发生形核结晶;（3）熔滴的非晶化还与雾化过程相关,由于熔滴破碎时的位置和温度不同,获得的冷却速率将不同,出现了相同直径（小于25 μm）的颗粒存在非晶和结晶两种状态.
2006, 35(6):871-875.
Abstract:
The energy and electronic structure of several Mg-Ce intermetallic compounds with different structure types were investigated using the first-principle pseudopotential plane-wave method. Based on the calculations of formation heat of and cohesive energies, their structural stability was analyzed. The results show that the structure types with the strongest alloying ability and the highest structural stability are DO3, C15, Ba, C15 and DO3, respectively, for the Mg3Ce, Mg2Ce, MgCe, MgCe2, MgCe3 intermetallic compounds. After compared the DOS (density of state) of these phases with different structure types, the results show that the discrepancy in structural stability of Mg-Ce intermetallic compounds can be attributed to the difference in the bonding electron numbers at Feimi level, which mainly originates from the contribution of valence electrons of Mg(3s), Mg(2p), Ce(5d) and Ce(4f) orbits. The less the valence electrons at Feimi level, the better the structural stability of Mg-Ce intermetallic compounds.
The energy and electronic structure of several Mg-Ce intermetallic compounds with different structure types were investigated using the first-principle pseudopotential plane-wave method. Based on the calculations of formation heat of and cohesive energies, their structural stability was analyzed. The results show that the structure types with the strongest alloying ability and the highest structural stability are DO3, C15, Ba, C15 and DO3, respectively, for the Mg3Ce, Mg2Ce, MgCe, MgCe2, MgCe3 intermetallic compounds. After compared the DOS (density of state) of these phases with different structure types, the results show that the discrepancy in structural stability of Mg-Ce intermetallic compounds can be attributed to the difference in the bonding electron numbers at Feimi level, which mainly originates from the contribution of valence electrons of Mg(3s), Mg(2p), Ce(5d) and Ce(4f) orbits. The less the valence electrons at Feimi level, the better the structural stability of Mg-Ce intermetallic compounds.
2006, 35(6):880-884.
Abstract:
采用AnyCasting软件模拟研究了模具内浇口尺寸、压射速度等因素对半固态ZL201合金触变压铸充型过程的影响.结果表明：压铸温度640℃,模具温度200℃～240℃,内浇口厚度11mm,低速阶段的压射速度0.1 m/s,高速阶段的压射速度1 m/s,在充型60%时进行速度切换,半固态浆料将以层流方式充填型腔,模拟结果与实际符合很好.半固态压铸件经T5处理后,硬度（HV）可达到1166 MPa,高于常规压铸件45.7%.
采用AnyCasting软件模拟研究了模具内浇口尺寸、压射速度等因素对半固态ZL201合金触变压铸充型过程的影响.结果表明：压铸温度640℃,模具温度200℃～240℃,内浇口厚度11mm,低速阶段的压射速度0.1 m/s,高速阶段的压射速度1 m/s,在充型60%时进行速度切换,半固态浆料将以层流方式充填型腔,模拟结果与实际符合很好.半固态压铸件经T5处理后,硬度（HV）可达到1166 MPa,高于常规压铸件45.7%.
2006, 35(6):885-889.
Abstract:
The thermal stress for Al/Ti coatings on uranium substrate was analyzed by using a thermal elastic plastic finite element method (FEM). The results indicate that the thermal stress is compressive inside the Ti coating and tensile inside the Al coating, which reaches the yield strength of Al. There is an uneven thermal stress distribution at the free side of specimen due to the end effect, which is vanished gradually at about 2h (where h is the coating thickness) from the free side of specimen. The shear stress of U-Al at the free side is larger than that in the middle of specimen. The effect of deposition temperature, coating thickness and mechanical properties on the thermal stress and plastic strain in coatings were also investigated. The results show that the thermal stress and plastic strain increase remarkably with the deposition temperature increasing. It is helpful to decrease the thermal stress and plastic strain by decreasing the thickness of Al coating and increasing the thickness of Ti coating. The yield strength of Al coating and the elastic modulus of Ti coating have large effects on the thermal stress and plastic strain of the coatings.
The thermal stress for Al/Ti coatings on uranium substrate was analyzed by using a thermal elastic plastic finite element method (FEM). The results indicate that the thermal stress is compressive inside the Ti coating and tensile inside the Al coating, which reaches the yield strength of Al. There is an uneven thermal stress distribution at the free side of specimen due to the end effect, which is vanished gradually at about 2h (where h is the coating thickness) from the free side of specimen. The shear stress of U-Al at the free side is larger than that in the middle of specimen. The effect of deposition temperature, coating thickness and mechanical properties on the thermal stress and plastic strain in coatings were also investigated. The results show that the thermal stress and plastic strain increase remarkably with the deposition temperature increasing. It is helpful to decrease the thermal stress and plastic strain by decreasing the thickness of Al coating and increasing the thickness of Ti coating. The yield strength of Al coating and the elastic modulus of Ti coating have large effects on the thermal stress and plastic strain of the coatings.
2006, 35(6):890-894.
Abstract:
用原位SEM观测研究了粉末冶金BeAl材料应力控制的疲劳机制.断裂时,低应力疲劳比高应力的平均累积塑性应变小得多.前者的累积塑性应变变化速率随着循环次数增大明显减小,后者则接近线性变化规律,表明高应力水平下的疲劳损伤累积更接近线性假设.低应力疲劳可从表面观测到一条疲劳主裂纹,由微观尺度下的累积塑性应变控制;高应力水平疲劳加载初期很快有宏观尺度的累积塑性应变,使Be与Al结合相界面同时产生较多裂纹.裂纹主要沿Al和Be结合强度较弱的表面路径扩展,随后沿纵深方向扩展,在材料内部裂纹扩展方向会变为与加载方向平行的Be基滑移面方向.当裂纹达到临界尺寸,局部塑性应变控制变为主应力方向控制,促使裂纹向前方扩展,宏观断口呈现出有层次的撕裂型.
用原位SEM观测研究了粉末冶金BeAl材料应力控制的疲劳机制.断裂时,低应力疲劳比高应力的平均累积塑性应变小得多.前者的累积塑性应变变化速率随着循环次数增大明显减小,后者则接近线性变化规律,表明高应力水平下的疲劳损伤累积更接近线性假设.低应力疲劳可从表面观测到一条疲劳主裂纹,由微观尺度下的累积塑性应变控制;高应力水平疲劳加载初期很快有宏观尺度的累积塑性应变,使Be与Al结合相界面同时产生较多裂纹.裂纹主要沿Al和Be结合强度较弱的表面路径扩展,随后沿纵深方向扩展,在材料内部裂纹扩展方向会变为与加载方向平行的Be基滑移面方向.当裂纹达到临界尺寸,局部塑性应变控制变为主应力方向控制,促使裂纹向前方扩展,宏观断口呈现出有层次的撕裂型.
2006, 35(6):895-899.
Abstract:
建立了几何拓扑模型和热应力拓扑模型,从这2种拓扑模型的结构、形状和对称性、特别是多次对称轴之间的关系,深入分析了角端、边缘、表层、内部4种淬火模型以及淬火角端效应和动态薄膜效应之间的内在联系,并指出了各种具体的工业实际应用.淬火过程中,热力学拓扑模型的对称轴(特别是n次对称轴)将以变化的θ角围绕几何拓扑模型的对称轴(特别是n次对称轴)不停转动,θ的大小由几何拓扑模型和动态薄膜共同决定,θ=0°或θ很小时,是理想状态层状分布热应力,θ较大甚至接近90°时,发生淬火角端效应和淬火动态薄膜效应.并且热力学拓扑模型的对称轴(特别是n次对称轴)指向的表面出现拉应力,和该轴成垂直方向的表面出现压应力.
建立了几何拓扑模型和热应力拓扑模型,从这2种拓扑模型的结构、形状和对称性、特别是多次对称轴之间的关系,深入分析了角端、边缘、表层、内部4种淬火模型以及淬火角端效应和动态薄膜效应之间的内在联系,并指出了各种具体的工业实际应用.淬火过程中,热力学拓扑模型的对称轴(特别是n次对称轴)将以变化的θ角围绕几何拓扑模型的对称轴(特别是n次对称轴)不停转动,θ的大小由几何拓扑模型和动态薄膜共同决定,θ=0°或θ很小时,是理想状态层状分布热应力,θ较大甚至接近90°时,发生淬火角端效应和淬火动态薄膜效应.并且热力学拓扑模型的对称轴(特别是n次对称轴)指向的表面出现拉应力,和该轴成垂直方向的表面出现压应力.
2006, 35(6):905-909.
Abstract:
以氧氯化锆(ZrOCl2·8H2O)为反应物,采用熔体反应法,并在反应过程中施加脉冲涡流磁场,磁化学合成了(Al2O3+Al3Zr)p/Al复合材料.扫描电镜(SEM)与X射线衍射(XRD)分析表明生成的颗粒为α-Al2O3和Al3Zr,颗粒细小,形状一致,且弥散分布于铝基体中;在相同反应条件下,与常规原位反应相比,磁场下反应更快、更完全,缩短了反应时间,并从反应动力学角度进行了分析.复合材料的力学性能研究表明,其屈服强度σs和抗拉强度σb均随颗粒体积分数的增加而升高,延伸率δ先升后降.(Al2O3+Al3Zr)p/Al复合材料的拉伸断口形貌表明,其断裂属塑性断裂.
以氧氯化锆(ZrOCl2·8H2O)为反应物,采用熔体反应法,并在反应过程中施加脉冲涡流磁场,磁化学合成了(Al2O3+Al3Zr)p/Al复合材料.扫描电镜(SEM)与X射线衍射(XRD)分析表明生成的颗粒为α-Al2O3和Al3Zr,颗粒细小,形状一致,且弥散分布于铝基体中;在相同反应条件下,与常规原位反应相比,磁场下反应更快、更完全,缩短了反应时间,并从反应动力学角度进行了分析.复合材料的力学性能研究表明,其屈服强度σs和抗拉强度σb均随颗粒体积分数的增加而升高,延伸率δ先升后降.(Al2O3+Al3Zr)p/Al复合材料的拉伸断口形貌表明,其断裂属塑性断裂.
2006, 35(6):913-916.
Abstract:
研究了微量钪对Al-Zn-Mg-Cu-Zr合金组织性能的影响,钪在铝合金中主要以2种形式的化合物存在,一种是合金凝固时从熔体中析出的一次Al3（Sc,Zr）相,另一种是合金铸锭均匀化时析出的二次Al3（Sc,Zr）相,前者是α（Al）晶粒细化剂,有效细化铸态晶粒,而二次Al3（Sc,Zr）粒子强烈钉扎晶粒内位错及亚晶界,有效阻止热轧、退火或固溶处理过程中合金再结晶.钪是产生强烈析出强化效应的合金元素,含0.30%Sc的Al-Zn-Mg-Cu-Zr合金的抗拉强度和延性显著高于不加钪的铝合金.
研究了微量钪对Al-Zn-Mg-Cu-Zr合金组织性能的影响,钪在铝合金中主要以2种形式的化合物存在,一种是合金凝固时从熔体中析出的一次Al3（Sc,Zr）相,另一种是合金铸锭均匀化时析出的二次Al3（Sc,Zr）相,前者是α（Al）晶粒细化剂,有效细化铸态晶粒,而二次Al3（Sc,Zr）粒子强烈钉扎晶粒内位错及亚晶界,有效阻止热轧、退火或固溶处理过程中合金再结晶.钪是产生强烈析出强化效应的合金元素,含0.30%Sc的Al-Zn-Mg-Cu-Zr合金的抗拉强度和延性显著高于不加钪的铝合金.
2006, 35(6):917-920.
Abstract:
用金相显微分析、DSC和VSM方法研究了Co40.5Ni34Al25.5合金马氏体相变和Curie点随淬火温度的变化,通过三点弯曲试验研究其形状记忆效果.结果发现该合金马氏体相变温度和Curie点与淬火温度成正比关系.马氏体相变的4种温度,即Ms,Mf,As和Af基本平行变化,淬火温度每升高10℃,马氏体相变温度和Curie点升高8℃～9℃.β相中Al的含量随淬火温度升高而降低,因而使马氏体相变温度和Curie点升高.1320℃淬火的Co40.5Ni34Al25.5合金的弯曲强度约为450 MPa,弯曲试验表明Co40.5Ni34Al25.5合金有双向形状记忆特性.
用金相显微分析、DSC和VSM方法研究了Co40.5Ni34Al25.5合金马氏体相变和Curie点随淬火温度的变化,通过三点弯曲试验研究其形状记忆效果.结果发现该合金马氏体相变温度和Curie点与淬火温度成正比关系.马氏体相变的4种温度,即Ms,Mf,As和Af基本平行变化,淬火温度每升高10℃,马氏体相变温度和Curie点升高8℃～9℃.β相中Al的含量随淬火温度升高而降低,因而使马氏体相变温度和Curie点升高.1320℃淬火的Co40.5Ni34Al25.5合金的弯曲强度约为450 MPa,弯曲试验表明Co40.5Ni34Al25.5合金有双向形状记忆特性.
2006, 35(6):921-924.
Abstract:
The LUMO-HOMO energy gaps in YBa2Cu3O7 have been calculated with density functional method (DFT) on a cluster model of unit cell in a wide range of temperatures (5 K~300 K). The results show that the superconducting energy gap (2?(T)) is about 80 meV at Tc (93 K), and decreases smoothly as the temperature increasing. It reaches the minimum at Tc and exhibits pseudogap above Tc. The pseudogap value reaches the maximum at T*(120 K) when the temperature increasing. The calculations by the cluster model of YBa2Cu3O6 unit cell show that the energy gap is about 102meV with characteristic gap of semiconductor.
The LUMO-HOMO energy gaps in YBa2Cu3O7 have been calculated with density functional method (DFT) on a cluster model of unit cell in a wide range of temperatures (5 K~300 K). The results show that the superconducting energy gap (2?(T)) is about 80 meV at Tc (93 K), and decreases smoothly as the temperature increasing. It reaches the minimum at Tc and exhibits pseudogap above Tc. The pseudogap value reaches the maximum at T*(120 K) when the temperature increasing. The calculations by the cluster model of YBa2Cu3O6 unit cell show that the energy gap is about 102meV with characteristic gap of semiconductor.
2006, 35(6):925-928.
Abstract:
研究了稀土、钙元素低合金化对AZ31镁合金板材力学性能、弯曲及拉胀复合成形性能的影响.结果表明：加入0.3%RE,0.3Ca%（质量分数,下同）后,AZ31镁合金板材的晶粒较细、力学性能明显提高,300℃,4 h退火后室温抗拉强度为284 MPa、延伸率为23.2%：同时,该合金板材具有最好的弯曲及拉胀复合成形性能,随着温度的提高其成形性能进一步提高.
研究了稀土、钙元素低合金化对AZ31镁合金板材力学性能、弯曲及拉胀复合成形性能的影响.结果表明：加入0.3%RE,0.3Ca%（质量分数,下同）后,AZ31镁合金板材的晶粒较细、力学性能明显提高,300℃,4 h退火后室温抗拉强度为284 MPa、延伸率为23.2%：同时,该合金板材具有最好的弯曲及拉胀复合成形性能,随着温度的提高其成形性能进一步提高.
2006, 35(6):929-932.
Abstract:
当GH761合金中的硼含量控制在正常值时,将磷含量从0.007%提高到0.023%,合金的650℃/637 MPa持久寿命从245 h提高到975 h,增幅达3倍.保持磷含量为0.023%,将硼含量提高到0.011%或以上时,合金的持久寿命显著降低.在实验含量范围内,磷、硼对合金的室温拉伸和650℃拉伸均无明显影响.磷、硼的最佳控制含量位于0.023%和0.005%附近.分析表明,当硼含量为正常值时,适量提高磷含量有助于改善合金的晶界析出,提高合金的持久性能.当加入适量磷时,进一步提高硼含量,将导致晶界析出过量,降低持久性能.
当GH761合金中的硼含量控制在正常值时,将磷含量从0.007%提高到0.023%,合金的650℃/637 MPa持久寿命从245 h提高到975 h,增幅达3倍.保持磷含量为0.023%,将硼含量提高到0.011%或以上时,合金的持久寿命显著降低.在实验含量范围内,磷、硼对合金的室温拉伸和650℃拉伸均无明显影响.磷、硼的最佳控制含量位于0.023%和0.005%附近.分析表明,当硼含量为正常值时,适量提高磷含量有助于改善合金的晶界析出,提高合金的持久性能.当加入适量磷时,进一步提高硼含量,将导致晶界析出过量,降低持久性能.
Zhang Jiuxing
,
Zhang Guozhen
,
Zhang Liping
,
Wang Che
,
Song Xiaoyan
,
Zhou Moiling
,
Zhong Taoxing
2006, 35(6):937-940.
Abstract:
The WC bulk was in-situ synthesized with mixed WO3 +14.5%C powders by spark plasma sintering at different temperatures. The chemical valence state of W, C, O in the samples were investigated by XPS. The results indicates that the element W changes from W+6, W+5, W+4 in oxidative state to metallic W0 and W+2 in carbide state with the rising of synthesizing temperature. It reveals that WO3 is firstly reduced by carbon to form intermediate tungsten oxides such as WO2.72, WO2, and metallic W in the reduction process, then the carbonization reaction occurs, and the WC is formed finally.
The WC bulk was in-situ synthesized with mixed WO3 +14.5%C powders by spark plasma sintering at different temperatures. The chemical valence state of W, C, O in the samples were investigated by XPS. The results indicates that the element W changes from W+6, W+5, W+4 in oxidative state to metallic W0 and W+2 in carbide state with the rising of synthesizing temperature. It reveals that WO3 is firstly reduced by carbon to form intermediate tungsten oxides such as WO2.72, WO2, and metallic W in the reduction process, then the carbonization reaction occurs, and the WC is formed finally.
2006, 35(6):941-944.
Abstract:
以Al-Li合金为对象,通过DSC技术研究了合金的相变.确定了相变温度范围、类型及其微观机理,确立了相变动力学计算方法,并以此计算了δ＇相的析出和溶解的激活能.研究表明：δ＇相析出为一级反应机制、δ＇相溶解则为三维扩散机制;在本实验条件下,δ＇相的析出激活能为188 kJ/mol～214 kJ/mol,δ＇相的溶解激活能为158 kJ/mol～228kJ/mol.根据实验和分析,可以认为采用热分析动力学方法能定量地表征Al-Li合金的相变.
以Al-Li合金为对象,通过DSC技术研究了合金的相变.确定了相变温度范围、类型及其微观机理,确立了相变动力学计算方法,并以此计算了δ＇相的析出和溶解的激活能.研究表明：δ＇相析出为一级反应机制、δ＇相溶解则为三维扩散机制;在本实验条件下,δ＇相的析出激活能为188 kJ/mol～214 kJ/mol,δ＇相的溶解激活能为158 kJ/mol～228kJ/mol.根据实验和分析,可以认为采用热分析动力学方法能定量地表征Al-Li合金的相变.
2006, 35(6):945-949.
Abstract:
分别以柠檬酸和碱式碳酸镍、乳酸和硝酸铁为原料,采用有机凝胶-热还原法分别成功制备了超细（直径＜1 μm）金属镍纤维和铁纤维,镍纤维长2 m,铁纤维长0.5 m,组成2种纤维的晶粒约100 nm.通过FTIR,XRD,TG/DSC和SEM对纤维前驱体凝胶的结构、热分解过程及热还原产物的形貌进行了表征.凝胶的可纺性与组成凝胶的羧酸盐分子结构有关.柠檬酸和乳酸中的羟基分别单齿配位于Ni^2＋和Fe^3＋离子,可能形成线型分子[（C6H6O7）Ni]n和[C3H4O3]3Fe,由这些线型分子组成的凝胶显示出了良好的可纺性.同时,可能由于在柠檬酸与Ni2＋离子的反应中存在Ni2＋离子的架桥作用,因而柠檬酸镍凝胶显示出了比乳酸铁凝胶更好的可纺性.
分别以柠檬酸和碱式碳酸镍、乳酸和硝酸铁为原料,采用有机凝胶-热还原法分别成功制备了超细（直径＜1 μm）金属镍纤维和铁纤维,镍纤维长2 m,铁纤维长0.5 m,组成2种纤维的晶粒约100 nm.通过FTIR,XRD,TG/DSC和SEM对纤维前驱体凝胶的结构、热分解过程及热还原产物的形貌进行了表征.凝胶的可纺性与组成凝胶的羧酸盐分子结构有关.柠檬酸和乳酸中的羟基分别单齿配位于Ni^2＋和Fe^3＋离子,可能形成线型分子[（C6H6O7）Ni]n和[C3H4O3]3Fe,由这些线型分子组成的凝胶显示出了良好的可纺性.同时,可能由于在柠檬酸与Ni2＋离子的反应中存在Ni2＋离子的架桥作用,因而柠檬酸镍凝胶显示出了比乳酸铁凝胶更好的可纺性.
2006, 35(6):950-953.
Abstract:
以H3BO3作助熔剂,用高温固相法在1400℃、保温4 h的条件下成功制备了LaMgAl11O19：Tb单相粉末样品并研究了其紫外光、真空紫外光激发下的一系列发光特性.在紫外光（254 nm）、真空紫外光（147 nm）激发下,观察到Tb^3＋很强的^5D4→^7FJ（=6,5,4,3）的跃迁发光.分析了LaMgAl11O19：Tb^3＋的发光强度与Tb^3＋掺杂浓度的关系.
以H3BO3作助熔剂,用高温固相法在1400℃、保温4 h的条件下成功制备了LaMgAl11O19：Tb单相粉末样品并研究了其紫外光、真空紫外光激发下的一系列发光特性.在紫外光（254 nm）、真空紫外光（147 nm）激发下,观察到Tb^3＋很强的^5D4→^7FJ（=6,5,4,3）的跃迁发光.分析了LaMgAl11O19：Tb^3＋的发光强度与Tb^3＋掺杂浓度的关系.
2006, 35(6):954-958.
Abstract:
对金溶胶的水相合成工艺中的搅拌时间以及试剂的加入量进行了实验研究,探讨了搅拌时间对金溶胶特征参数和稳定性的影响.研究中发现金溶胶制备完毕后,继续搅拌会破坏金溶胶的稳定.在所配的试剂浓度的条件下,柠檬酸钠溶液的用量在不大于2 ml时都可以制备稳定的金溶胶,并且金溶胶的吸光度随氯金酸用量的增加而线性增加.
对金溶胶的水相合成工艺中的搅拌时间以及试剂的加入量进行了实验研究,探讨了搅拌时间对金溶胶特征参数和稳定性的影响.研究中发现金溶胶制备完毕后,继续搅拌会破坏金溶胶的稳定.在所配的试剂浓度的条件下,柠檬酸钠溶液的用量在不大于2 ml时都可以制备稳定的金溶胶,并且金溶胶的吸光度随氯金酸用量的增加而线性增加.
2006, 35(6):959-962.
Abstract:
在以Triton X-100为表面活性剂形成的反相胶束体系中,成功地制备了半导体硫化银纳米管,管径88 nm～120nm、长度大于2.6 μm.X射线衍射测定表明,产物为纯单斜结构.紫外-可见光谱在275 nm处发现新的吸收峰,最大发射波长与体相材料相比,蓝移了38 nm.
在以Triton X-100为表面活性剂形成的反相胶束体系中,成功地制备了半导体硫化银纳米管,管径88 nm～120nm、长度大于2.6 μm.X射线衍射测定表明,产物为纯单斜结构.紫外-可见光谱在275 nm处发现新的吸收峰,最大发射波长与体相材料相比,蓝移了38 nm.
2006, 35(6):963-965.
Abstract:
用自蔓延(SHS)法成功制备了MgB2超导块材.B,Mg合成MgB2是放热反应,预热温度和真空度是影响MgB2性能的主要因素,当预热温度太低时不能用电弧引导反应,理论计算和实验结果表明预热温度应该大于484 K,但预热温度太高会使部分MgB2分解为MgB4和MgB7,当预热温度为520K,真空度为2.4×10-3Pa时,试样的临界温度Tc=38.45K,温度转变宽度小于0.4 K,临界电流密度Jc=1.60×106A/cm2(10 K,0.5 T),1.65×106A/cm2(20 K,0 T).试样的致密度较低时,结构为层状,层与层之间有空洞,每层由颗粒状晶粒组成,颗粒尺寸为2 μm～5 μm.SHS法制备MgB2超导块材工艺简单、反应时间短(3 s～5 s).
用自蔓延(SHS)法成功制备了MgB2超导块材.B,Mg合成MgB2是放热反应,预热温度和真空度是影响MgB2性能的主要因素,当预热温度太低时不能用电弧引导反应,理论计算和实验结果表明预热温度应该大于484 K,但预热温度太高会使部分MgB2分解为MgB4和MgB7,当预热温度为520K,真空度为2.4×10-3Pa时,试样的临界温度Tc=38.45K,温度转变宽度小于0.4 K,临界电流密度Jc=1.60×106A/cm2(10 K,0.5 T),1.65×106A/cm2(20 K,0 T).试样的致密度较低时,结构为层状,层与层之间有空洞,每层由颗粒状晶粒组成,颗粒尺寸为2 μm～5 μm.SHS法制备MgB2超导块材工艺简单、反应时间短(3 s～5 s).
2006, 35(6):966-969.
Abstract:
A backside growth technique of thick porous silicon layers for the on-chip RF integrated inductor is presented. ASITIC calculation confirms that the thick porous silicon substrate (through the wafer) is a better choice to achieve high quality factor RF integrated inductors. Fabrication and characterization of the through wafer PS layer with the backside growth technique were carried out, which proved the feasibility of post-processing procedure in CMOS technology. ESEM was used to observe the morphologies of the fabricated samples. The relationships of PS growth rate as a function of current density was concluded.
A backside growth technique of thick porous silicon layers for the on-chip RF integrated inductor is presented. ASITIC calculation confirms that the thick porous silicon substrate (through the wafer) is a better choice to achieve high quality factor RF integrated inductors. Fabrication and characterization of the through wafer PS layer with the backside growth technique were carried out, which proved the feasibility of post-processing procedure in CMOS technology. ESEM was used to observe the morphologies of the fabricated samples. The relationships of PS growth rate as a function of current density was concluded.
2006, 35(6):970-973.
Abstract:
借助金相显微镜研究了Sr对AZ91镁合金铸态显微组织的影响.结果表明,少量的Sr（0.2%～0.5%,质量分数,下同）对合金的铸态组织具有明显细化作用,并增加合金的密度.进一步增加Sr含量,合金组织有粗化倾向,而且形成杆状Al4Sr新相.利用差热分析和电子探针研究了合金铸态组织的细化机制.
借助金相显微镜研究了Sr对AZ91镁合金铸态显微组织的影响.结果表明,少量的Sr（0.2%～0.5%,质量分数,下同）对合金的铸态组织具有明显细化作用,并增加合金的密度.进一步增加Sr含量,合金组织有粗化倾向,而且形成杆状Al4Sr新相.利用差热分析和电子探针研究了合金铸态组织的细化机制.
2006, 35(6):974-977.
Abstract:
采用高速火焰（HVOF）热喷涂工艺制备了金属间化合物NiAl-Ta-Cr涂层.研究了喷涂距离、氧气流量以及燃气流量等工艺参数对涂层组织结构和性能的影响.用光学显微镜观察涂层的组织结构并测定涂层的孔隙率,用LECOTC316气体抽提仪检测涂层的氧含量.结果表明,氧气流量、喷涂距离等工艺参数对涂层性能的影响比较明显.随着喷涂距离的增加,涂层的氧含量降低;O/H比率越大,涂层的氧含量越高,而孔隙率降低,沉积率越高.涂层经1100℃,4 h真空热处理后,变得更加均匀和致密,孔隙率降低,但涂层的硬度有所降低.涂层经1100℃,100 h高温氧化处理后,在涂层表面生成了连续的氧化铝氧化层,硬度比真空退火后略有下降.
采用高速火焰（HVOF）热喷涂工艺制备了金属间化合物NiAl-Ta-Cr涂层.研究了喷涂距离、氧气流量以及燃气流量等工艺参数对涂层组织结构和性能的影响.用光学显微镜观察涂层的组织结构并测定涂层的孔隙率,用LECOTC316气体抽提仪检测涂层的氧含量.结果表明,氧气流量、喷涂距离等工艺参数对涂层性能的影响比较明显.随着喷涂距离的增加,涂层的氧含量降低;O/H比率越大,涂层的氧含量越高,而孔隙率降低,沉积率越高.涂层经1100℃,4 h真空热处理后,变得更加均匀和致密,孔隙率降低,但涂层的硬度有所降低.涂层经1100℃,100 h高温氧化处理后,在涂层表面生成了连续的氧化铝氧化层,硬度比真空退火后略有下降.
2006, 35(6):978-981.
Abstract:
The Nb-Si-N films were deposited by reactive magnetron sputtering with different N2 partial pressures. The result showed that the composition, microstructure and properties of the Nb-Si-N films depend strongly on the N2 partial pressure. As the N2 partial pressure increasing, the Nb/Si ratio and the surface roughness decease, but the bulk resistance and microhardness of the Nb-Si-N films increase. The microstructure of Nb-Si-N films is a nano-composite structure consisting of nano-sized NbN crystallites and amorphous Si3N4-like compound of Si-N. With the increase of N2 partial pressure, the amorphous tendency of Nb-Si-N films increases and the grain size decreases.
The Nb-Si-N films were deposited by reactive magnetron sputtering with different N2 partial pressures. The result showed that the composition, microstructure and properties of the Nb-Si-N films depend strongly on the N2 partial pressure. As the N2 partial pressure increasing, the Nb/Si ratio and the surface roughness decease, but the bulk resistance and microhardness of the Nb-Si-N films increase. The microstructure of Nb-Si-N films is a nano-composite structure consisting of nano-sized NbN crystallites and amorphous Si3N4-like compound of Si-N. With the increase of N2 partial pressure, the amorphous tendency of Nb-Si-N films increases and the grain size decreases.
2006, 35(6):982-985.
Abstract:
The effects of stir velocity, slurry viscosity and density on the porosity were studied and the porosity was characterized by using the Reynolds number according to the bubble forming theory in this paper. It is found that the porosity is the same if the Reynolds number is the same regardless different stir velocity, slurry viscosity or slurry density. The quantitative functional relationships between the porosity and Reynolds number was deduced.
The effects of stir velocity, slurry viscosity and density on the porosity were studied and the porosity was characterized by using the Reynolds number according to the bubble forming theory in this paper. It is found that the porosity is the same if the Reynolds number is the same regardless different stir velocity, slurry viscosity or slurry density. The quantitative functional relationships between the porosity and Reynolds number was deduced.
2006, 35(6):986-989.
Abstract:
研究在微波段具有高磁导率和大磁损耗的CoFeZrRE薄膜,采用射频磁控溅射工艺制备该类薄膜,探讨了工艺参数和薄膜厚度对CoFeZrRE薄膜结构和电磁性能的影响.重点研究了掺杂稀土元素的含量和种类对薄膜磁各向异性、饱和磁化强度等基本磁参量以及微波磁导率和磁损耗的影响.结果表明,重稀土元素（如Dy,Tb）提高微波磁损耗的效果更显著;CoFeZrRE类薄膜具有较高的微波磁导率和磁损耗（2 GHz处,μ＇和μ＂均高于200）,有望在微波吸收和抗电磁干扰领域获得广泛应用.
研究在微波段具有高磁导率和大磁损耗的CoFeZrRE薄膜,采用射频磁控溅射工艺制备该类薄膜,探讨了工艺参数和薄膜厚度对CoFeZrRE薄膜结构和电磁性能的影响.重点研究了掺杂稀土元素的含量和种类对薄膜磁各向异性、饱和磁化强度等基本磁参量以及微波磁导率和磁损耗的影响.结果表明,重稀土元素（如Dy,Tb）提高微波磁损耗的效果更显著;CoFeZrRE类薄膜具有较高的微波磁导率和磁损耗（2 GHz处,μ＇和μ＂均高于200）,有望在微波吸收和抗电磁干扰领域获得广泛应用.
2006, 35(6):990-993.
Abstract:
The La2NiO4 metalloid conductive ceramics produced by conventional ceramic preparation technique were added into fine silver powders to form Ag/La2NiO4 composite contact materials. It is found by XRD that the phase structure of La2NiO4 ceramics did not change after arc erosion and exhibited a high chemical stability. The test results of model life and mechanical and physical properties show that the mass transfer and erosion is less and the performance of surface anti-erosion is more favorable for the contacts, resulting in the small resistivity and good mechanical properties. The Ag/La2NiO4 contacts exhibit an excellent performance compared with the Ag/CdO and Ag/SnO2 contact materials and very possible for the new type of contact materials as environmentally acceptable alternative to Ag/CdO.
The La2NiO4 metalloid conductive ceramics produced by conventional ceramic preparation technique were added into fine silver powders to form Ag/La2NiO4 composite contact materials. It is found by XRD that the phase structure of La2NiO4 ceramics did not change after arc erosion and exhibited a high chemical stability. The test results of model life and mechanical and physical properties show that the mass transfer and erosion is less and the performance of surface anti-erosion is more favorable for the contacts, resulting in the small resistivity and good mechanical properties. The Ag/La2NiO4 contacts exhibit an excellent performance compared with the Ag/CdO and Ag/SnO2 contact materials and very possible for the new type of contact materials as environmentally acceptable alternative to Ag/CdO.
2006, 35(6):994-997.
Abstract:
The surface structure was characterized by XRD, SEM, XPS and FTIR for the NiTi shape memory alloy (SMA) with a nearly-equiatomic ratio after composite bioactive treatment in H2O2 and subsequent NaOH solutions. The biomimetic deposition process of apatite coatings on the pretreated NiTi SMA was studied in the simulated body fluid (SBF). The experimental results indicate that a wormlike bioactive layer with many Ti-OH groups and a trait of Ni2O3 is formed on the NiTi substrate after the composite bioactive treatment, which was mainly composed of the poorly-crystallized Na2TiO3 and TiO2 and relatively poor in Ni. The bioactive layer can induce the apatite nucleation and growth in SBF and obtain an ideal apatite coating on NiTi substrate in a short term.
The surface structure was characterized by XRD, SEM, XPS and FTIR for the NiTi shape memory alloy (SMA) with a nearly-equiatomic ratio after composite bioactive treatment in H2O2 and subsequent NaOH solutions. The biomimetic deposition process of apatite coatings on the pretreated NiTi SMA was studied in the simulated body fluid (SBF). The experimental results indicate that a wormlike bioactive layer with many Ti-OH groups and a trait of Ni2O3 is formed on the NiTi substrate after the composite bioactive treatment, which was mainly composed of the poorly-crystallized Na2TiO3 and TiO2 and relatively poor in Ni. The bioactive layer can induce the apatite nucleation and growth in SBF and obtain an ideal apatite coating on NiTi substrate in a short term.
2006, 35(6):998-1001.
Abstract:
采用电弧炉坩埚浇铸法制备Zr50Cu40Al10三元锆基块体非晶,研究了电磁搅拌合金熔体的作用.结果表明,虽然在该方法中合金熔体是仅在重力作用下自由充填铸模型腔,但与常用的真空吸铸铜模铸造法相比,铸模对合金熔体的激冷能力并没有明显的降低.电磁搅拌可减小合金熔体与坩埚底部由于欧姆接触所造成的“晶核污染”,因而使锆基块体非晶态合金具有更宽的过冷液相区温度范围△Tx和更高的热稳定性.
采用电弧炉坩埚浇铸法制备Zr50Cu40Al10三元锆基块体非晶,研究了电磁搅拌合金熔体的作用.结果表明,虽然在该方法中合金熔体是仅在重力作用下自由充填铸模型腔,但与常用的真空吸铸铜模铸造法相比,铸模对合金熔体的激冷能力并没有明显的降低.电磁搅拌可减小合金熔体与坩埚底部由于欧姆接触所造成的“晶核污染”,因而使锆基块体非晶态合金具有更宽的过冷液相区温度范围△Tx和更高的热稳定性.
2006, 35(6):1002-1005.
Abstract:
利用电化学极化曲线测量、氧化增重测量、往复式摩擦磨损实验,对分别通过阳极氧化和高压釜氧化生成的2种不同Zr-4合金表面氧化膜的耐腐蚀、耐高温氧化和抗摩擦性能进行测试和对比评价.实验表明,2种氧化膜都有效地改善了Zr-4合金的性能（耐腐蚀,耐高温氧化等）,它们对Zr-4合金的改善程度相近.XRD,XPS,RBS,SEM等方法分析表明,阳极氧化膜厚度约1μm,分为疏松水合层和ZrO2致密层2部分,ZrO2由四方相和单斜相组成;高压釜预生膜厚度约0.9μm,分为最外H2O层、疏松水合层和ZrO2致密层3部分,ZrO2只以单斜相存在.研究结果为现行核工业中对Zr-4合金的预处理方法提供了一个新的思路.
利用电化学极化曲线测量、氧化增重测量、往复式摩擦磨损实验,对分别通过阳极氧化和高压釜氧化生成的2种不同Zr-4合金表面氧化膜的耐腐蚀、耐高温氧化和抗摩擦性能进行测试和对比评价.实验表明,2种氧化膜都有效地改善了Zr-4合金的性能（耐腐蚀,耐高温氧化等）,它们对Zr-4合金的改善程度相近.XRD,XPS,RBS,SEM等方法分析表明,阳极氧化膜厚度约1μm,分为疏松水合层和ZrO2致密层2部分,ZrO2由四方相和单斜相组成;高压釜预生膜厚度约0.9μm,分为最外H2O层、疏松水合层和ZrO2致密层3部分,ZrO2只以单斜相存在.研究结果为现行核工业中对Zr-4合金的预处理方法提供了一个新的思路.
2006, 35(6):1006-1008.
Abstract:
The effect of annealing process on the microstructure and magnetic properties of sintered NdFeB magnets were studied. The results show that the microstructure of magnets is ameliorated after annealing. The grain boundary became smoother and clearer, the Nd-rich phase distributed surrounding the grain dispersedly and equably, and the boundary phase became stable and well-proportioned. Therefore, the coercive force was remarkably enhanced, the residual magnetism and (BH) max were increased at the same time, and thermal stability of the magnet was improved enormously.
The effect of annealing process on the microstructure and magnetic properties of sintered NdFeB magnets were studied. The results show that the microstructure of magnets is ameliorated after annealing. The grain boundary became smoother and clearer, the Nd-rich phase distributed surrounding the grain dispersedly and equably, and the boundary phase became stable and well-proportioned. Therefore, the coercive force was remarkably enhanced, the residual magnetism and (BH) max were increased at the same time, and thermal stability of the magnet was improved enormously.
