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铜基合金的双向形状记忆效应研究进展 总被引:1,自引:0,他引:1
综述了铜基合金有关双向形状记忆效应的训练方法、组织结构、训练机理及性能稳定性等方面的研究进展,并指出了有待深入研究的问题。 相似文献
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Nb-22Ti-14Si-2Hf-2Al-xCr (x=2, 6, 10, 14, 17 at%) alloys are prepared by arc-melting under argon atmosphere. Microstructural characteristics, mechanical properties and oxidation resistance of the arc-melted alloys are investigated. At 2 at% Cr content, the microstructure is composed of Nbss, Nb3Si and a small quantity of Nb5Si3, when the Cr contents increase, Nb3Si disappears. For the high Cr content (x ≥ 10 at%) alloys, besides the Nbss and Nb5Si3, Cr2Nb is also detected. With the increase of Cr content, the volume fractions of Cr2Nb and Nb5Si3 increase, while that of Nbss increases firstly and then begins to degrade when the Cr content is higher than 6 at%. For the alloy with 2 at% Cr, the room temperature fracture toughness is about 14.5 MPa·m1/2, but badly decreases to about 8.5 MPa·m1/2, when the Cr contents increase. Vickers hardness of Nbss tends to increase linearly from about 400 to 500, while that of silicides is not sensitive to Cr contents, about 950. The appearance of Cr2Nb phase significantly improves the high temperature oxidation resistance of the alloys with high Cr contents. The isothermal oxidation tests show that the oxidation kinetics of the alloys with various Cr contents follows parabolic oxidation kinetics. 相似文献
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非晶晶化制备细晶TiAl基合金 总被引:2,自引:1,他引:2
采用X ray衍射,DTA以及扫描电镜分析了Ti 50at%Al元素混合粉末高能球磨和热压过程中的结构演变和致密TiAl基合金的显微结构。结果表明,Ti 50at%Al粉末经过100h的高能球磨后转化为无序非晶相,Ti和Al元素粉末在机械合金化过程中的结构演变为:Ti Al→Ti(Al)过饱和固溶体(hcp)→非晶相。Ti 50at%Al非晶粉末在随后的热压过程中发生晶化,得到晶粒尺寸约为0.5μm的细晶TiAl基合金。Ti 50at%Al非晶的晶化过程为:非晶相→无序α相(hcp)→γ TiAl相( α2 Ti3Al相),其中α相是由无序非晶相向有序γ TiAl相转化过程中的介稳相。根据热压后γ TiAl相的不规则块状形貌推测α→γ TiAl转变的机制可能为块型转变。 相似文献
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本文综述了铝锂合金疲劳的研究进展,包括铝锂合金的疲劳长裂纹、短裂纹、裂纹萌生、光滑和缺口疲劳强度、循环应变行为、过载反应、低温疲劳和腐蚀疲劳、铝锂合金与2000和7000系铝合金疲劳性能的对比、热处理工艺、微观结构、合金成分等对铝锂合金疲劳性能的影响等。 相似文献
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采用磁悬浮区域熔炼的方法,制备了PST晶体,在800℃对其压缩性能进行了测试,并对其变形组织进行了观察。结果表明,在800℃时的屈服强度取决于片层界面与压缩轴的夹角,在=90°时屈服强度为最高,而=45°为最低。800°时屈服强度有较大程度的下降,这与α2相中锥面滑移系{1121}〈1126〉的临界分切应力的降低有关。 相似文献
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