Volume 34,Issue 2,2005 Table of Contents
2005, 34(2):169-173.
Abstract:
Two powder metallurgic methods of manufacturing TiAl based alloy sheet, including elemental powder metallurgy and pre-alloying powder metallurgy, are briefly reviewed. And the fabricating processes and materials properties of elemental powder metallurgy, elemental foil powder metallurgy, hot rolling of pre-alloyed powders, physical vapor deposition and plasma spraying are introduced. Meanwhile, the process characteristics and prospects for these techniques are also described.
Two powder metallurgic methods of manufacturing TiAl based alloy sheet, including elemental powder metallurgy and pre-alloying powder metallurgy, are briefly reviewed. And the fabricating processes and materials properties of elemental powder metallurgy, elemental foil powder metallurgy, hot rolling of pre-alloyed powders, physical vapor deposition and plasma spraying are introduced. Meanwhile, the process characteristics and prospects for these techniques are also described.
2005, 34(2):174-177.
Abstract:
介绍了Ti-V-Ni，Ti-V-Mn和Ti-V-Cr3种固溶体合金作为储氢合金或电极材料的研究现状。对无电化学活性的基质合金，用元素取代、合成复合合金和多相合金等多种方法，得到一些性能较好的负极材料。同时指出了固溶体合金的特点和研究工作的方向。
介绍了Ti-V-Ni，Ti-V-Mn和Ti-V-Cr3种固溶体合金作为储氢合金或电极材料的研究现状。对无电化学活性的基质合金，用元素取代、合成复合合金和多相合金等多种方法，得到一些性能较好的负极材料。同时指出了固溶体合金的特点和研究工作的方向。
2005, 34(2):178-183.
Abstract:
The concept and the development background of titanium matrix functionally gradient materials(FGM)complex structure are introduced.The macro-meso-scopic scale of research results of FGM are reviewed and the development trends in the area are prospected.By gradually varying the volume fraction of the constituent materials, their material properties exhibit a smooth and continuous change with respect to the spatial location, thus being void of interface problems that are usually associated with fiber-reinforced composites and with less severe thermal stress concentrations. FGMs are now developed for general use as structural components in extremely high temperature environments. The current status of research and the application prospects for materials optimization analysis of FGM complex structure are especially discussed.Future research needs are highlighted.
The concept and the development background of titanium matrix functionally gradient materials(FGM)complex structure are introduced.The macro-meso-scopic scale of research results of FGM are reviewed and the development trends in the area are prospected.By gradually varying the volume fraction of the constituent materials, their material properties exhibit a smooth and continuous change with respect to the spatial location, thus being void of interface problems that are usually associated with fiber-reinforced composites and with less severe thermal stress concentrations. FGMs are now developed for general use as structural components in extremely high temperature environments. The current status of research and the application prospects for materials optimization analysis of FGM complex structure are especially discussed.Future research needs are highlighted.
2005, 34(2):184-188.
Abstract:
The precipitates size distribution and morphology in an Al-Zn-Mg-Cu-Li alloy are studied by small angle X-ray scattering and transmission electron microscopy. The results show that the precipitates belong to ellipsoid and their axis ratio range is between 0.2 and 0.4, aged under different conditions. The logarithm Gaussian distribution of effective size and the Maxwell distribution of particles mass with gyration radius are also constructed. The changing of both types of distribution curves with kinetic strength Ks has been analyzed.. The results show that the geometric average and distribution width for both types of distribution curves increase with kinetic strength.
The precipitates size distribution and morphology in an Al-Zn-Mg-Cu-Li alloy are studied by small angle X-ray scattering and transmission electron microscopy. The results show that the precipitates belong to ellipsoid and their axis ratio range is between 0.2 and 0.4, aged under different conditions. The logarithm Gaussian distribution of effective size and the Maxwell distribution of particles mass with gyration radius are also constructed. The changing of both types of distribution curves with kinetic strength Ks has been analyzed.. The results show that the geometric average and distribution width for both types of distribution curves increase with kinetic strength.
2005, 34(2):189-193.
Abstract:
通过研究GPS烧结氮化硅陶瓷的室温和高温抗弯强度、晶界相含量和成分以及晶界析晶相随氮化硅粉料表面氧含量的变化规律，发现当粉料表面氧含量低于1．35mg／m^2时，氮化硅陶瓷在室温下的抗弯强度基本保持不变。试样在1200℃时的抗弯强度明显低于室温强度，且随着粉料表面氧含量的增加有一最高值。由于烧结助剂引入的O和Si在烧结过程中的还原气氛下发生反应而损失，烧结体中晶界相的实际含量显著低于粉料中烧结助剂的加入量。随粉料表面氧含量的增加，氮化硅陶瓷烧结体中的二次析晶相α-Y2Si2O7和β-Y2Si2O7消失，只有β-Si3N4晶相和晶界玻璃相存在。
通过研究GPS烧结氮化硅陶瓷的室温和高温抗弯强度、晶界相含量和成分以及晶界析晶相随氮化硅粉料表面氧含量的变化规律，发现当粉料表面氧含量低于1．35mg／m^2时，氮化硅陶瓷在室温下的抗弯强度基本保持不变。试样在1200℃时的抗弯强度明显低于室温强度，且随着粉料表面氧含量的增加有一最高值。由于烧结助剂引入的O和Si在烧结过程中的还原气氛下发生反应而损失，烧结体中晶界相的实际含量显著低于粉料中烧结助剂的加入量。随粉料表面氧含量的增加，氮化硅陶瓷烧结体中的二次析晶相α-Y2Si2O7和β-Y2Si2O7消失，只有β-Si3N4晶相和晶界玻璃相存在。
2005, 34(2):194-198.
Abstract:
用金相显微镜、定量金相、扫描电镜(SEM)、能谱分析(EDX)及X射线衍射(XRD)研究了0％，4％，6％Ta(质量分数)3种成分的低Cr高W铸造镍基高温合金铸态及热暴露后的显微组织，结果表明：Ta是强MC碳化物形成元素，它形成MC碳化物的倾向低于Nb、高于Ti，当合金中Ta的原子百分含量超过Nb3倍时，Ta在MC碳化物中的原子百分含量超过Nb。Ta是强γ'形成元素，它促进共晶γ’的形成，在合金成分中以等量原子百分含量的Ta代替Al不会改变合金的共晶γ'数量。在高W铸造高温合金中M6C是比MC更加稳定的碳化物，Ta的加入不能抑制1100℃，500h长时热暴露后MC完全转变为粒状或片状M6C。MC分解时释放的碳还促使σ(W,Mo) C→M6C反应。对Ni-1．5Cr-10Co-16W-2Mo-5Al-1Ti-1Nb基础成分合金，其最佳的含Ta量为4％(质量分数)，而且含碳量应低于0．07％(质量分数)。
用金相显微镜、定量金相、扫描电镜(SEM)、能谱分析(EDX)及X射线衍射(XRD)研究了0％，4％，6％Ta(质量分数)3种成分的低Cr高W铸造镍基高温合金铸态及热暴露后的显微组织，结果表明：Ta是强MC碳化物形成元素，它形成MC碳化物的倾向低于Nb、高于Ti，当合金中Ta的原子百分含量超过Nb3倍时，Ta在MC碳化物中的原子百分含量超过Nb。Ta是强γ'形成元素，它促进共晶γ’的形成，在合金成分中以等量原子百分含量的Ta代替Al不会改变合金的共晶γ'数量。在高W铸造高温合金中M6C是比MC更加稳定的碳化物，Ta的加入不能抑制1100℃，500h长时热暴露后MC完全转变为粒状或片状M6C。MC分解时释放的碳还促使σ(W,Mo) C→M6C反应。对Ni-1．5Cr-10Co-16W-2Mo-5Al-1Ti-1Nb基础成分合金，其最佳的含Ta量为4％(质量分数)，而且含碳量应低于0．07％(质量分数)。
2005, 34(2):205-207.
Abstract:
在已有的泡沫金属双向名义载荷强度与孔隙率关系的基础上，分析了该材料的双向等应力拉伸加载情形，探讨了泡沫金属在该情形下发生破坏的力学行为。研究结果显示，以“八面体模型”推导出来的有关力学关系，较好地表征了该材料在双向等载条件下的行为特点。
在已有的泡沫金属双向名义载荷强度与孔隙率关系的基础上，分析了该材料的双向等应力拉伸加载情形，探讨了泡沫金属在该情形下发生破坏的力学行为。研究结果显示，以“八面体模型”推导出来的有关力学关系，较好地表征了该材料在双向等载条件下的行为特点。
2005, 34(2):212-216.
Abstract:
In order to modify its cycle stability, a trace amount of boron was added in low-Co AB5-type hydrogen storage alloy. The low-Co AB5-type MmNi3.8Co0.4Mn0.6Al0.2B(x=0, 0.1, 0.2, 0.3, 0.4)hydrogen storage alloys were prepared by cast and rapid quenching. The x microstructures and electrochemical performances of the as-cast and quenched alloys were analyzed and measured. The effect of boron additive on the microstructures and cycle lives of the alloys were investigated comprehensively. The experimental results show that the addition of boron dramatically enhances the cycle lives of the as-cast and quenched low-Co AB5-type hydrogen storage alloys, whereas the action mechanism of boron is completely different.
In order to modify its cycle stability, a trace amount of boron was added in low-Co AB5-type hydrogen storage alloy. The low-Co AB5-type MmNi3.8Co0.4Mn0.6Al0.2B(x=0, 0.1, 0.2, 0.3, 0.4)hydrogen storage alloys were prepared by cast and rapid quenching. The x microstructures and electrochemical performances of the as-cast and quenched alloys were analyzed and measured. The effect of boron additive on the microstructures and cycle lives of the alloys were investigated comprehensively. The experimental results show that the addition of boron dramatically enhances the cycle lives of the as-cast and quenched low-Co AB5-type hydrogen storage alloys, whereas the action mechanism of boron is completely different.
9 Investigation on Low Cycle Fatigue and Fracture Behaviors of Directionally Solidified DZ4 Superalloy
2005, 34(2):217-220.
Abstract:
对定向凝固DZ4合金760℃和800℃下的低周疲劳行为进行了研究，并结合断口观察，对其疲劳裂纹的萌生与扩展进行了分析。结果表明，DZ4合金760℃和800℃下的低周疲劳属应力疲劳，其损伤以弹性损伤为主，弹性损伤与疲劳寿命具有很好的相关性。定向凝固DZ4合金高寿命低周疲劳裂纹易于萌生于试样内部或亚表面的柱状晶界。其疲劳裂纹的稳定扩展也较难形成典型的疲劳条带。
对定向凝固DZ4合金760℃和800℃下的低周疲劳行为进行了研究，并结合断口观察，对其疲劳裂纹的萌生与扩展进行了分析。结果表明，DZ4合金760℃和800℃下的低周疲劳属应力疲劳，其损伤以弹性损伤为主，弹性损伤与疲劳寿命具有很好的相关性。定向凝固DZ4合金高寿命低周疲劳裂纹易于萌生于试样内部或亚表面的柱状晶界。其疲劳裂纹的稳定扩展也较难形成典型的疲劳条带。
2005, 34(2):221-225.
Abstract:
The molybdenum sheets doped with different contents of La2O3 (Mo-La2O3) were prepared by powder metallurgy and processing technology. Then their mechanical properties were tested by use of tension at room temperature with different velocity and their microstructures were discussed by means of SEM, TEM and XRD. It is shown that both the strength and ductility of molybdenum sheets are greatly improved by addition of La2O3. The maximum elongation of annealed Mo- La2O3 sheets is up to 46%. The experimental results can be reasonably explained by the interaction of La2O3 particles and dislocation as well as the toughening of second phase La2O3 .
The molybdenum sheets doped with different contents of La2O3 (Mo-La2O3) were prepared by powder metallurgy and processing technology. Then their mechanical properties were tested by use of tension at room temperature with different velocity and their microstructures were discussed by means of SEM, TEM and XRD. It is shown that both the strength and ductility of molybdenum sheets are greatly improved by addition of La2O3. The maximum elongation of annealed Mo- La2O3 sheets is up to 46%. The experimental results can be reasonably explained by the interaction of La2O3 particles and dislocation as well as the toughening of second phase La2O3 .
2005, 34(2):226-230.
Abstract:
用金相显微镜，扫描电镜，X射线衍射及密度测定，研究了90W-7Ni-3Fe和80W-10Ta-7Ni-3Fe2种成分合金。结果表明，含Ta合金在1400℃烧结时密度可达96.3％，合金密度随烧结温度提高而增加，在1460℃时密度达到最大；Ta原子固溶到硬质相W和粘结相中，使得合金硬度明显提高；含Ta合金断口形貌中，粘结相呈沿晶断裂、W晶粒穿晶断裂及其脱出具有相当比例；Ta粉末粒度对合金力学性能、微观组织及断裂方式均产生显著影响。
用金相显微镜，扫描电镜，X射线衍射及密度测定，研究了90W-7Ni-3Fe和80W-10Ta-7Ni-3Fe2种成分合金。结果表明，含Ta合金在1400℃烧结时密度可达96.3％，合金密度随烧结温度提高而增加，在1460℃时密度达到最大；Ta原子固溶到硬质相W和粘结相中，使得合金硬度明显提高；含Ta合金断口形貌中，粘结相呈沿晶断裂、W晶粒穿晶断裂及其脱出具有相当比例；Ta粉末粒度对合金力学性能、微观组织及断裂方式均产生显著影响。
2005, 34(2):231-233.
Abstract:
利用电阻炉加热，采用电子显微镜及图象分析仪，研究了近液相线铸造A356铝合金在二次加热过程中的组织变化。结果表明：近液相线铸造铝合金A356在580℃～590℃加热，保温10min，晶粒仍保持细小、近似等轴的组织特点。随着加热温度的升高和保温时间的延长，初生相尺寸增加较小，具有较高的热稳定性。
利用电阻炉加热，采用电子显微镜及图象分析仪，研究了近液相线铸造A356铝合金在二次加热过程中的组织变化。结果表明：近液相线铸造铝合金A356在580℃～590℃加热，保温10min，晶粒仍保持细小、近似等轴的组织特点。随着加热温度的升高和保温时间的延长，初生相尺寸增加较小，具有较高的热稳定性。
2005, 34(2):234-239.
Abstract:
Directional solidification of peritectic alloy described is significant for advanced materials processing. The nucleation and growth mechanisms of peritectic phase are outlined and the nucleation undercooling of peritectic phase is small as a result of the presence of properitectic phase nuclei. On the basis of assuming maximal interface growth temperature or nucleation and constitutional undercooling criterion (NCU), the microstructure and phase selection of peritectic alloy have been considered. It was found that the peritectic reaction as one of the growth mechanisms of peritectic phase existed not only at the S/L interface, but also in the directionally solidified sample of Sn-Cu peritectic alloy. Finally, the problems for directional solidification of peritectic alloys were presented to deeply and rigorously explore the solidification theory and experiment of peritectic alloy.
Directional solidification of peritectic alloy described is significant for advanced materials processing. The nucleation and growth mechanisms of peritectic phase are outlined and the nucleation undercooling of peritectic phase is small as a result of the presence of properitectic phase nuclei. On the basis of assuming maximal interface growth temperature or nucleation and constitutional undercooling criterion (NCU), the microstructure and phase selection of peritectic alloy have been considered. It was found that the peritectic reaction as one of the growth mechanisms of peritectic phase existed not only at the S/L interface, but also in the directionally solidified sample of Sn-Cu peritectic alloy. Finally, the problems for directional solidification of peritectic alloys were presented to deeply and rigorously explore the solidification theory and experiment of peritectic alloy.
2005, 34(2):240-243.
Abstract:
测定了LaNi5-xAlx(x=0，0．1，0．2，0．3)系合金在吸放氢过程中的贮氢性能。结果表明，贮氢容量随合金中Al含量的增加而降低，平台压力和热力学焓变和熵变随合金中Al含量的增加而降低，合金形成氢化物的稳定性增强；LaNi5-xAlx系合金在吸放氢过程中的平台压力存在一定的差异，即滞后现象，滞后系数随合金中Al含量的增加而降低，这是LaNi5-xAlx系的晶胞体积随合金中Al含量的增加而增加的必然结果;LaNi5-xAlx系合金的吸放氢动力学参数也与合金中的Al含量有关，活化能随Al含量的增加而降低，但活化能不存在数量级的差异。
测定了LaNi5-xAlx(x=0，0．1，0．2，0．3)系合金在吸放氢过程中的贮氢性能。结果表明，贮氢容量随合金中Al含量的增加而降低，平台压力和热力学焓变和熵变随合金中Al含量的增加而降低，合金形成氢化物的稳定性增强；LaNi5-xAlx系合金在吸放氢过程中的平台压力存在一定的差异，即滞后现象，滞后系数随合金中Al含量的增加而降低，这是LaNi5-xAlx系的晶胞体积随合金中Al含量的增加而增加的必然结果;LaNi5-xAlx系合金的吸放氢动力学参数也与合金中的Al含量有关，活化能随Al含量的增加而降低，但活化能不存在数量级的差异。
2005, 34(2):244-247.
Abstract:
采用凝胶注模技术原位合成造孔剂制备出开孔气孔率为20％～30％的La0．8Sr0．2MnO3多孔阴极材料。结果表明，合适的烧结温度为l100℃～1150℃；开口气孔位于三角晶界，中位孔径约为400nm；多孔材料的电导率随着温度的升高而升高，由ln(σT)-1／T曲线，可得电导活化能Ea为10．99kJ／mol。
采用凝胶注模技术原位合成造孔剂制备出开孔气孔率为20％～30％的La0．8Sr0．2MnO3多孔阴极材料。结果表明，合适的烧结温度为l100℃～1150℃；开口气孔位于三角晶界，中位孔径约为400nm；多孔材料的电导率随着温度的升高而升高，由ln(σT)-1／T曲线，可得电导活化能Ea为10．99kJ／mol。
2005, 34(2):248-251.
Abstract:
Nano-Al2O3 dispersion strengthened Ni-based alloy coatings produced by crosscurrent CO2 laser on Ni-based superalloy are introduced. Cross-section of the coatings have been examined to reveal their microstructure, using optical microscope and SEM (including EDS microanalysis). The results show that rapid directional solidification of epitaxy is found at the interface where the growth direction is perpendicular to the bottom of melting pool. The size of columnar dendrite is decreased by adding Al2O3 nanocrystalline to the powder. A novel microstructure of equiaxed solidification has been observed with the increasing a mount of Al2O3 to 1% (in weight). Fine and equiaxed microstructure has been obtained for the nanocrystalline Al2O3 acting as new nucleation site of the melting pool.
Nano-Al2O3 dispersion strengthened Ni-based alloy coatings produced by crosscurrent CO2 laser on Ni-based superalloy are introduced. Cross-section of the coatings have been examined to reveal their microstructure, using optical microscope and SEM (including EDS microanalysis). The results show that rapid directional solidification of epitaxy is found at the interface where the growth direction is perpendicular to the bottom of melting pool. The size of columnar dendrite is decreased by adding Al2O3 nanocrystalline to the powder. A novel microstructure of equiaxed solidification has been observed with the increasing a mount of Al2O3 to 1% (in weight). Fine and equiaxed microstructure has been obtained for the nanocrystalline Al2O3 acting as new nucleation site of the melting pool.
2005, 34(2):252-255.
Abstract:
研究了向原料粉中掺加Al粉对合成高纯致密Ti3SiC2材料的影响。实验表明以2TiC／1Ti／1Si／0．2Al为起始原料组成，采用热压工艺在1200℃～1400℃的温度范围内，可以制备得到密度达到理论密度98％以上的高纯致密Ti3SiC2块体材料。由XRD数据计算得到的晶格参数与文献中的值接近。通过SEM和EPMA分析得知Ti3SiC2晶粒呈板状结晶形貌，且发育良好，晶粒在平面内的尺寸分别为3μm～8μm和4μm～10μm。
研究了向原料粉中掺加Al粉对合成高纯致密Ti3SiC2材料的影响。实验表明以2TiC／1Ti／1Si／0．2Al为起始原料组成，采用热压工艺在1200℃～1400℃的温度范围内，可以制备得到密度达到理论密度98％以上的高纯致密Ti3SiC2块体材料。由XRD数据计算得到的晶格参数与文献中的值接近。通过SEM和EPMA分析得知Ti3SiC2晶粒呈板状结晶形貌，且发育良好，晶粒在平面内的尺寸分别为3μm～8μm和4μm～10μm。
2005, 34(2):256-258.
Abstract:
Blue luminescence at about 431nm is obtained from epitaxial silicon after sequential processing of C+ implantation, annealing in hydrogen ambience and chemical etching. With the increase of chemical etching, the blue peak was enhanced at first, decreased then and substituted by a red peak at last. C=O compounds induced during C+ implantation are embedded in the surface of nanometer Si formed during annealing, and nanometer silicon with embedded structure is formed at last, which contributes to the blue emission.
Blue luminescence at about 431nm is obtained from epitaxial silicon after sequential processing of C+ implantation, annealing in hydrogen ambience and chemical etching. With the increase of chemical etching, the blue peak was enhanced at first, decreased then and substituted by a red peak at last. C=O compounds induced during C+ implantation are embedded in the surface of nanometer Si formed during annealing, and nanometer silicon with embedded structure is formed at last, which contributes to the blue emission.
2005, 34(2):259-262.
Abstract:
采用磁控溅射方法在Si(111)基片上沉积Cu-Zr／ZrN薄膜体系作为扩散阻挡层。通过比较Cu-Zr／ZrN薄膜体系和三元非晶(Mo，Ta，W)-Si-N的电阻率，同时比较Cu-Zr／ZrN薄膜体系和Ta，TaN的硬度，说明作为扩散阻挡层的材料的选取，应从整体性能上考虑，而不能仅仅考虑热稳定性等单一指标。
采用磁控溅射方法在Si(111)基片上沉积Cu-Zr／ZrN薄膜体系作为扩散阻挡层。通过比较Cu-Zr／ZrN薄膜体系和三元非晶(Mo，Ta，W)-Si-N的电阻率，同时比较Cu-Zr／ZrN薄膜体系和Ta，TaN的硬度，说明作为扩散阻挡层的材料的选取，应从整体性能上考虑，而不能仅仅考虑热稳定性等单一指标。
2005, 34(2):263-265.
Abstract:
采用示差扫描量热法(DSC)，X射线衍射(XRD)和振动样品磁强计(VSM)研究了Nd60Fe20Al10-xCo10Bx(x=0，2，5)大块非晶合金的结构、磁性能和晶化行为。结果表明：Nd60Fe20Al10-xCo10Bx非晶合金在晶化前既没有发生玻璃转变也没有过冷液相区；Nd60Fe20Al10Co10合金的DSC曲线上在360℃～475℃之间有1个宽的放热峰，加入2at％～5at％的B后该放热峰消失。铸态Nd60Fe20Al10-xCo10Bx(x=0，2，5)大块非晶合金在室温具有硬磁性。随B含量的增加，合金的内禀矫顽力显著增加，而饱和磁化强度和剩磁则有所下降。B的加入使Nd60Fe20Al10Co10合金的晶化行为发生明显变化。
采用示差扫描量热法(DSC)，X射线衍射(XRD)和振动样品磁强计(VSM)研究了Nd60Fe20Al10-xCo10Bx(x=0，2，5)大块非晶合金的结构、磁性能和晶化行为。结果表明：Nd60Fe20Al10-xCo10Bx非晶合金在晶化前既没有发生玻璃转变也没有过冷液相区；Nd60Fe20Al10Co10合金的DSC曲线上在360℃～475℃之间有1个宽的放热峰，加入2at％～5at％的B后该放热峰消失。铸态Nd60Fe20Al10-xCo10Bx(x=0，2，5)大块非晶合金在室温具有硬磁性。随B含量的增加，合金的内禀矫顽力显著增加，而饱和磁化强度和剩磁则有所下降。B的加入使Nd60Fe20Al10Co10合金的晶化行为发生明显变化。
2005, 34(2):266-270.
Abstract:
Ferromagnetic Ni-Mn-Fe-Ga single crystal of a pseudoquaternary Heusler alloy has been invested as a new magnetic field control actuator material. A single crystal of Ni52Mn16.4Fe8Ga23.6 was grown in [001] direction of the cubic parent phase by the Czochralski method. The field-controlled shape memory effect and the temperature dependent of the magnetic-field-induced strain (MFIS) in Ni52Mn16.4Fe8Ga23.6 single crystal were investigated by measuring the field enhanced transformation strain and the MFIS with a magnetic field applied in different directions. The results show that such material combined with the martensitic transformation can produce the large field-enhanced transformation strain and the large MFIS. It is found that the MFIS is almost temperature independent, the maximum decreasing magnitude of the saturated MFIS is less than 10% from 265 K to 100 K. In addition, the direction in which the MFIS has the largest value is always the [001], namely the growth direction of the crystals. The results are discussed with reference to the shape memory characteristics of the alloys and the mechanism of the preferentially orientation of martensitic variants.
Ferromagnetic Ni-Mn-Fe-Ga single crystal of a pseudoquaternary Heusler alloy has been invested as a new magnetic field control actuator material. A single crystal of Ni52Mn16.4Fe8Ga23.6 was grown in [001] direction of the cubic parent phase by the Czochralski method. The field-controlled shape memory effect and the temperature dependent of the magnetic-field-induced strain (MFIS) in Ni52Mn16.4Fe8Ga23.6 single crystal were investigated by measuring the field enhanced transformation strain and the MFIS with a magnetic field applied in different directions. The results show that such material combined with the martensitic transformation can produce the large field-enhanced transformation strain and the large MFIS. It is found that the MFIS is almost temperature independent, the maximum decreasing magnitude of the saturated MFIS is less than 10% from 265 K to 100 K. In addition, the direction in which the MFIS has the largest value is always the [001], namely the growth direction of the crystals. The results are discussed with reference to the shape memory characteristics of the alloys and the mechanism of the preferentially orientation of martensitic variants.
2005, 34(2):271-274.
Abstract:
采用粉冶法制备了添加Y2O3／CeO2(≤0．6w％)的复合强化钼合金(MYC)丝。用XRD标定合金相组成，用SEM观察合金的显微组织，用万能电子拉伸机测定合金丝的力学性能并将测定结果与纯钼丝进行了对比研究。研究结果表明：添加Y2O3／CeO2复合强化钼合金的相组成为Mo，YMoO4和CeO2；MYC合金断口具有典型的塑性断裂特征，MYC合金丝在1600℃退火后仍然表现明显的纤维状织构组织形态。
采用粉冶法制备了添加Y2O3／CeO2(≤0．6w％)的复合强化钼合金(MYC)丝。用XRD标定合金相组成，用SEM观察合金的显微组织，用万能电子拉伸机测定合金丝的力学性能并将测定结果与纯钼丝进行了对比研究。研究结果表明：添加Y2O3／CeO2复合强化钼合金的相组成为Mo，YMoO4和CeO2；MYC合金断口具有典型的塑性断裂特征，MYC合金丝在1600℃退火后仍然表现明显的纤维状织构组织形态。
2005, 34(2):275-278.
Abstract:
The high temperature reaction between H2 and Ga2O3 is employed to obtain constant surface source of Ga, then high uniformity doping of Ga in Si is realized through SiO2-Si compound structure. By characterizing means of SIMS, SRP and four-point probe meter, the thermal distribution of P-type dopant Ga in SiO2 films, at the internal surface of SiO2-Si and near Si surface is analyzed respectively. The essence of open-tube Ga diffusion is revealed, which is closely related with both the rapid transportation of Ga through SiO2 film and the segregation effect of it at the internal surface of SiO2-Si. The mechanism of Ga concentration distribution is discussed accordingly.
The high temperature reaction between H2 and Ga2O3 is employed to obtain constant surface source of Ga, then high uniformity doping of Ga in Si is realized through SiO2-Si compound structure. By characterizing means of SIMS, SRP and four-point probe meter, the thermal distribution of P-type dopant Ga in SiO2 films, at the internal surface of SiO2-Si and near Si surface is analyzed respectively. The essence of open-tube Ga diffusion is revealed, which is closely related with both the rapid transportation of Ga through SiO2 film and the segregation effect of it at the internal surface of SiO2-Si. The mechanism of Ga concentration distribution is discussed accordingly.
24 The Photocatalytic Killing Effect of Surface Fractal Dimension of TiO2 Film on Human Gastric Cancer
2005, 34(2):279-282.
Abstract:
采用涂覆法制备了作为光催化剂的TiO2薄膜。XRD和SEM分析表明：所制备的TiO2为锐钛型；薄膜表面呈现均匀的结构；微晶平均粒度为22．7nm。在体外对胃癌细胞进行了紫外光照TiO2光催化的实验，并同仅用紫外光和仅用TiO2的空白实验作了对照。用盒子维模型计算了所制备的催化剂表面分形维数。结果表明：所制备的纳米TiO2催化剂表面分形维数介于2．52～2．57。分形维数较大的TiO2薄膜，对胃癌细胞的杀伤效果较好，杀伤率达80％。
采用涂覆法制备了作为光催化剂的TiO2薄膜。XRD和SEM分析表明：所制备的TiO2为锐钛型；薄膜表面呈现均匀的结构；微晶平均粒度为22．7nm。在体外对胃癌细胞进行了紫外光照TiO2光催化的实验，并同仅用紫外光和仅用TiO2的空白实验作了对照。用盒子维模型计算了所制备的催化剂表面分形维数。结果表明：所制备的纳米TiO2催化剂表面分形维数介于2．52～2．57。分形维数较大的TiO2薄膜，对胃癌细胞的杀伤效果较好，杀伤率达80％。
2005, 34(2):283-286.
Abstract:
Phase structure and electrochemical properties of the storage hydrogen electrode alloys Zr1-xTix(Mn0.7V0.2 Co0.1Ni1.2)were investigated by XRD,SEM and EPMA, and electrochemical properties of the alloys were examined. The matrix alloys consisted of cubic C15 Laves phase and second phase (Zr7M10). With the increasing of Ti content, the lattice parameter of alloys decreased and C14 Laves phase appeared and increased. A little of TiNi phase appeared at x=0.1~0.2; however, Zr7M10 phase and TiNi phase decomposed at x=0.4~0.5, which demonstrated that high Ti content inhibited the appearance of second phase in the alloys. As a result, the storage hydrogen electrode alloy Zr0.8Ti0.2(Mn0.7V0.2Co0.1Ni1.2), the maximum discharge capacity of which is 354 mAh/g, possesses good rate capability. This contributes to change phase structure and phase composition, which plays a synergetic role in the charge-discharge process.
Phase structure and electrochemical properties of the storage hydrogen electrode alloys Zr1-xTix(Mn0.7V0.2 Co0.1Ni1.2)were investigated by XRD,SEM and EPMA, and electrochemical properties of the alloys were examined. The matrix alloys consisted of cubic C15 Laves phase and second phase (Zr7M10). With the increasing of Ti content, the lattice parameter of alloys decreased and C14 Laves phase appeared and increased. A little of TiNi phase appeared at x=0.1~0.2; however, Zr7M10 phase and TiNi phase decomposed at x=0.4~0.5, which demonstrated that high Ti content inhibited the appearance of second phase in the alloys. As a result, the storage hydrogen electrode alloy Zr0.8Ti0.2(Mn0.7V0.2Co0.1Ni1.2), the maximum discharge capacity of which is 354 mAh/g, possesses good rate capability. This contributes to change phase structure and phase composition, which plays a synergetic role in the charge-discharge process.
2005, 34(2):287-290.
Abstract:
TiO2 nanotube was synthesized successfully by hydrothermal process, using TiO2 powder and NaOH as the precurser. The micro-morphology and optical properties were characterized by XRD, SEM, HRTEM, UV Absorption Spectra Analyzer and Spectroradiometer, and the formation mechanism was also studied. The results showed that the product is anatase TiO2 nanotube with multiple layers wall, 10 nm~50 nm in the out-diameter, several micron to tens in the length, and opened in both of ends. The formation mechanism of the tube is coordinate with 3-2-1D model. The UV Absorption Spectra and PL spectra showed that the TiO2 nanotubes present blue-shift phenomenon compared to the raw material. The PL spectra also showed that at the visible band the luminous intensity of the TiO2 nanotubes increased obviously.
TiO2 nanotube was synthesized successfully by hydrothermal process, using TiO2 powder and NaOH as the precurser. The micro-morphology and optical properties were characterized by XRD, SEM, HRTEM, UV Absorption Spectra Analyzer and Spectroradiometer, and the formation mechanism was also studied. The results showed that the product is anatase TiO2 nanotube with multiple layers wall, 10 nm~50 nm in the out-diameter, several micron to tens in the length, and opened in both of ends. The formation mechanism of the tube is coordinate with 3-2-1D model. The UV Absorption Spectra and PL spectra showed that the TiO2 nanotubes present blue-shift phenomenon compared to the raw material. The PL spectra also showed that at the visible band the luminous intensity of the TiO2 nanotubes increased obviously.
2005, 34(2):291-294.
Abstract:
用溶胶．凝胶(Sol-Gel)法制备了RE(RE=La，Y)-Mo复合氧化物粉末，工艺条件：初始溶液pH值=1，于550℃分解胶体，500℃，900℃ 2次还原粉末。采用XRD，TEM对还原后粉末的相组成、形貌、粒度进行分析。结果表明：500℃还原后，单质Mo衍射峰出现，RE以非晶态RE-O-Mo存在；900℃2次还原后，RE以氧化物形式存在。红外光谱(FT-IR)分析结果表明，La和Y通过O与Mo键合，削弱Mo=O键，使稀土钼复合氧化物可还原性增强。TEM分析表明，还原后稀土钼粉末粒径在70nm左右。
用溶胶．凝胶(Sol-Gel)法制备了RE(RE=La，Y)-Mo复合氧化物粉末，工艺条件：初始溶液pH值=1，于550℃分解胶体，500℃，900℃ 2次还原粉末。采用XRD，TEM对还原后粉末的相组成、形貌、粒度进行分析。结果表明：500℃还原后，单质Mo衍射峰出现，RE以非晶态RE-O-Mo存在；900℃2次还原后，RE以氧化物形式存在。红外光谱(FT-IR)分析结果表明，La和Y通过O与Mo键合，削弱Mo=O键，使稀土钼复合氧化物可还原性增强。TEM分析表明，还原后稀土钼粉末粒径在70nm左右。
2005, 34(2):295-298.
Abstract:
自行设计了电弧腐蚀速率的测量方法，避免了一般电弧腐蚀速率测量中存在的不足，并对真空断路器中常用的CuCr25，CuCr50触头材料以及纯Cu和纯Cr的电弧腐蚀速率进行了测量。研究结果表明，纯Cu，CuCr25，CuCr50和纯Cr的电弧腐蚀速率分别为52．9μg／C，33．2μg／C，31μg／C和25．9μg／C。CuCr25和CuCr50的电弧腐蚀速率相差不大，都较纯Cu有大幅度的降低，而与纯cr的电弧腐蚀速率比较接近。此外，用SEM对4种触头材料经100次燃弧之后的电极表面进行了现测，清楚地反映了经电弧腐蚀之后触角材料的表面特征。
自行设计了电弧腐蚀速率的测量方法，避免了一般电弧腐蚀速率测量中存在的不足，并对真空断路器中常用的CuCr25，CuCr50触头材料以及纯Cu和纯Cr的电弧腐蚀速率进行了测量。研究结果表明，纯Cu，CuCr25，CuCr50和纯Cr的电弧腐蚀速率分别为52．9μg／C，33．2μg／C，31μg／C和25．9μg／C。CuCr25和CuCr50的电弧腐蚀速率相差不大，都较纯Cu有大幅度的降低，而与纯cr的电弧腐蚀速率比较接近。此外，用SEM对4种触头材料经100次燃弧之后的电极表面进行了现测，清楚地反映了经电弧腐蚀之后触角材料的表面特征。
2005, 34(2):299-302.
Abstract:
采用DSC、弯曲实验和扫描电镜分析研究了热处理工艺对医用TiNi合金细丝显微组织、相变温度和形状记忆效应的影响。结果表明，400℃～500℃，30min～120min热处理时，随着温度的升高和时间的增长，TiNi合金细丝中Ti3Ni4析出相增多，相变温度也升高。细丝经500℃，30min处理后的最大可回复应变量值最大。随弯曲变形量的增加，疲劳寿命缩短。500℃处理的试样疲劳寿命最长。
采用DSC、弯曲实验和扫描电镜分析研究了热处理工艺对医用TiNi合金细丝显微组织、相变温度和形状记忆效应的影响。结果表明，400℃～500℃，30min～120min热处理时，随着温度的升高和时间的增长，TiNi合金细丝中Ti3Ni4析出相增多，相变温度也升高。细丝经500℃，30min处理后的最大可回复应变量值最大。随弯曲变形量的增加，疲劳寿命缩短。500℃处理的试样疲劳寿命最长。
30 Structure and Magnetic Properties of Nanocomposite Nd9Fe85-xB6Inx Prepared by Melt-Spinning Method
2005, 34(2):303-305.
Abstract:
Nanocomposite Nd9Fe85-xB6Inx magnets were synthesized by melt-spinning method. The effect between indium-dope and treating process on their magnetic properties were investigated by using XRD and VSM. The results show that both the coercivity and remanence ratio can be enhanced by a small indium-dope in Nd9Fe85B6 nanocomposite, while squareness of its hysteresis loop is also improved greatly. The optimum energy product increases remarkably from 95 kJ/m3 to 145 kJ/m3, while coercivity rises from 405 kA/m to 465 kA/m at 0~0.5 mol% indium-dope.
Nanocomposite Nd9Fe85-xB6Inx magnets were synthesized by melt-spinning method. The effect between indium-dope and treating process on their magnetic properties were investigated by using XRD and VSM. The results show that both the coercivity and remanence ratio can be enhanced by a small indium-dope in Nd9Fe85B6 nanocomposite, while squareness of its hysteresis loop is also improved greatly. The optimum energy product increases remarkably from 95 kJ/m3 to 145 kJ/m3, while coercivity rises from 405 kA/m to 465 kA/m at 0~0.5 mol% indium-dope.
2005, 34(2):306-308.
Abstract:
以单质Zn，Se和H2为原料，采用低压化学气相沉积方法在温度为630℃～750℃，压力为300Pa～1000Pa条件下制备出了性能优异的ZnSe多晶材料。性能测试表明，制备出的CVDZnSe多晶材料在0．55μm～22μm，及8μm～14μm波段的平均透过率超过70％(1mm厚)，在3．39μm处的应力双折射为54nm／cm。其光学透过性能与美国采用Zn和H2Se气体为原料制备出的CVD ZnSe多晶非常接近。
以单质Zn，Se和H2为原料，采用低压化学气相沉积方法在温度为630℃～750℃，压力为300Pa～1000Pa条件下制备出了性能优异的ZnSe多晶材料。性能测试表明，制备出的CVDZnSe多晶材料在0．55μm～22μm，及8μm～14μm波段的平均透过率超过70％(1mm厚)，在3．39μm处的应力双折射为54nm／cm。其光学透过性能与美国采用Zn和H2Se气体为原料制备出的CVD ZnSe多晶非常接近。
2005, 34(2):309-311.
Abstract:
采用电弧等离子体法成功制备了单晶态的纳米钽超微粒子，采用透射电子显微镜(TEM)、高分辨电子显微镜(HRTEM)对样品进行形貌、微观结构的观察和分析，发现它具有规则的表面，平均粒径大小在10am左右。并通过X射线衍射(XRD)分析其组成成分，发现在所制备的样品中除钽外还含有氧化钽(δ-TaO)，估计是由于纳米钽粒子被氧化所形成的产物。
采用电弧等离子体法成功制备了单晶态的纳米钽超微粒子，采用透射电子显微镜(TEM)、高分辨电子显微镜(HRTEM)对样品进行形貌、微观结构的观察和分析，发现它具有规则的表面，平均粒径大小在10am左右。并通过X射线衍射(XRD)分析其组成成分，发现在所制备的样品中除钽外还含有氧化钽(δ-TaO)，估计是由于纳米钽粒子被氧化所形成的产物。
2005, 34(2):312-315.
Abstract:
Gallium nitride (GaN) films have been successfully fabricated on silicon (111) substrates through ammoniating Ga2O3/Al2O3 films deposited by rf magnetron sputtering. The formed films were characterized by Fourier transform infrared (FTIR) transmission spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) , scanning electron microscopy (SEM) and photoluminescence spectrum(PL). The results indicate that the films formed are polycrystalline GaN with hexagonal wurtzite structure.
Gallium nitride (GaN) films have been successfully fabricated on silicon (111) substrates through ammoniating Ga2O3/Al2O3 films deposited by rf magnetron sputtering. The formed films were characterized by Fourier transform infrared (FTIR) transmission spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) , scanning electron microscopy (SEM) and photoluminescence spectrum(PL). The results indicate that the films formed are polycrystalline GaN with hexagonal wurtzite structure.
2005, 34(2):316-320.
Abstract:
Mgx/Mg2Ni(x=10%, 30%, 50%) composites were synthesized by ball milling the mixture of Mg2Ni alloys and Mg powder. XRD analysis show that no new phase was produced, and the decomposability of Mg2Ni phase existed in the milling of solo Mg2Ni alloys is restrained in the milling of Mg2Ni alloys and Mg powder. Electrochemical characteristics of Mgx/Mg2Ni composites at different milling time were evaluated by simulated battery test. It was found that the discharge capacity of Mgx/Mg2Ni composite was obviously improved with increasing content of Mg powder in the milling. The discharge capacity of the composites were enhanced with increasing milling time at the beginning of milling, while a decrease was followed. The relationship between discharge capacity and milling time was mainly influenced by the micstructure of composites caused by ball milling.
Mgx/Mg2Ni(x=10%, 30%, 50%) composites were synthesized by ball milling the mixture of Mg2Ni alloys and Mg powder. XRD analysis show that no new phase was produced, and the decomposability of Mg2Ni phase existed in the milling of solo Mg2Ni alloys is restrained in the milling of Mg2Ni alloys and Mg powder. Electrochemical characteristics of Mgx/Mg2Ni composites at different milling time were evaluated by simulated battery test. It was found that the discharge capacity of Mgx/Mg2Ni composite was obviously improved with increasing content of Mg powder in the milling. The discharge capacity of the composites were enhanced with increasing milling time at the beginning of milling, while a decrease was followed. The relationship between discharge capacity and milling time was mainly influenced by the micstructure of composites caused by ball milling.
2005, 34(2):321-324.
Abstract:
The preparation of metal-ceramic composite material, silver coated BaTiO3 powder, was investigated. The shape of single particle and congeries state were studied with SEM and laser particle size analysis. The existing state of silver on BaTiO3 was also discussed. Silver was deposited on BaTiO3 with chemical deposition method. Protected by surfactant, Ag(NH3)2 was reduced by hydrazine + hydrate, and the composite powder with excellent dispersibility was obtained. The optimal conditions are: concentration of silver 0.1%~ 0.5%, surfactant/ Ag(W/W)20%, the ratio of silver of composite powder < 80%, reaction time 120min and the concentration of hydrazine hydrate 0.8%. The particle size in SEM spectra and EDX analysis suggests that the particle is the composite material with silver coated BaTiO3.
The preparation of metal-ceramic composite material, silver coated BaTiO3 powder, was investigated. The shape of single particle and congeries state were studied with SEM and laser particle size analysis. The existing state of silver on BaTiO3 was also discussed. Silver was deposited on BaTiO3 with chemical deposition method. Protected by surfactant, Ag(NH3)2 was reduced by hydrazine + hydrate, and the composite powder with excellent dispersibility was obtained. The optimal conditions are: concentration of silver 0.1%~ 0.5%, surfactant/ Ag(W/W)20%, the ratio of silver of composite powder < 80%, reaction time 120min and the concentration of hydrazine hydrate 0.8%. The particle size in SEM spectra and EDX analysis suggests that the particle is the composite material with silver coated BaTiO3.
2005, 34(2):325-328.
Abstract:
用溶胶-凝胶(Sol-Gel)法制备了低介低烧堇青石陶瓷材料。用X射线衍射、热分析、扫描电镜等方法研究了该材料的低温烧结行为、析晶过程、烧结性能等。结果表明，该类材料能够在900℃下低温烧结，其烧结致密过程主要在750℃～900℃之间进行。烧结体的微观结构主要由占85％(按体积)、大小为50nm～150nm的α堇青石、少量玻璃相和气孔组成。该材料具有良好的介电性能(ε≤5，tgδ≤0．001：1GHz)，能够和银等电极低温共烧，是应用于高频片式电感等电子元器件以及高频陶瓷封装的理想介质材料。
用溶胶-凝胶(Sol-Gel)法制备了低介低烧堇青石陶瓷材料。用X射线衍射、热分析、扫描电镜等方法研究了该材料的低温烧结行为、析晶过程、烧结性能等。结果表明，该类材料能够在900℃下低温烧结，其烧结致密过程主要在750℃～900℃之间进行。烧结体的微观结构主要由占85％(按体积)、大小为50nm～150nm的α堇青石、少量玻璃相和气孔组成。该材料具有良好的介电性能(ε≤5，tgδ≤0．001：1GHz)，能够和银等电极低温共烧，是应用于高频片式电感等电子元器件以及高频陶瓷封装的理想介质材料。
2005, 34(2):329-333.
Abstract:
Ceramic-like coatings were formed using alternate ultra-narrow pulse microarc oxidation method on alloy Ti6Al4V in Na2SiO3-KOH-(NaPO3)6 aqueous solution. A constant voltage (U=500 V) regime of microarc oxidation was applied to reveal the effect of positive pulse duty cycle on their growth rate, microstructure and phase composition. In order to obtain the optimum process, a constant current density (J=60 mA/cm2) regime combined with the stepped adjusting of positive duty cycle during microarc oxidation process is also proposed. With the positive duty cycle increasing from 4 % to 20 %, the growth rate of the coatings increases and the surface morphology becomes coarser. The as-deposited coatings are mainly composed of anatase and rutile TiO2. With the pulse duration increasing, the content of anatase decreases, while rutile increases and becomes the predominant phase. Considering the microstructure and growing thickness of the coatings, 8 % of positive duty cycle is suitable. When applying the constant current density regime, the growth rate of coatings is significantly increased compared with that by the constant voltage regime. And the morphology of the coatings is obviously improved by using the stepped adjusting of duty cycle furthermore.
Ceramic-like coatings were formed using alternate ultra-narrow pulse microarc oxidation method on alloy Ti6Al4V in Na2SiO3-KOH-(NaPO3)6 aqueous solution. A constant voltage (U=500 V) regime of microarc oxidation was applied to reveal the effect of positive pulse duty cycle on their growth rate, microstructure and phase composition. In order to obtain the optimum process, a constant current density (J=60 mA/cm2) regime combined with the stepped adjusting of positive duty cycle during microarc oxidation process is also proposed. With the positive duty cycle increasing from 4 % to 20 %, the growth rate of the coatings increases and the surface morphology becomes coarser. The as-deposited coatings are mainly composed of anatase and rutile TiO2. With the pulse duration increasing, the content of anatase decreases, while rutile increases and becomes the predominant phase. Considering the microstructure and growing thickness of the coatings, 8 % of positive duty cycle is suitable. When applying the constant current density regime, the growth rate of coatings is significantly increased compared with that by the constant voltage regime. And the morphology of the coatings is obviously improved by using the stepped adjusting of duty cycle furthermore.
2005, 34(2):334-336.
Abstract:
The brazing-ability of Al2O3P/Cu Base Metal Matrix Composite and Nb with AgCuTi filler metal was studied. The results show that through adding active element Ti to the filler metal, the Al2O3P grains in the brazing seam are decreased or eliminated, and the concentration of Al2O3P grains in the seam is avoided. The ionic bond Al2O3P is transformed in to metalloid bond TiO, so that the matching-ability of the brazing seam substrate and the grain phase is enhanced.
The brazing-ability of Al2O3P/Cu Base Metal Matrix Composite and Nb with AgCuTi filler metal was studied. The results show that through adding active element Ti to the filler metal, the Al2O3P grains in the brazing seam are decreased or eliminated, and the concentration of Al2O3P grains in the seam is avoided. The ionic bond Al2O3P is transformed in to metalloid bond TiO, so that the matching-ability of the brazing seam substrate and the grain phase is enhanced.
