STRUCTURE CONTROLL AND IMPROVEMENT OF HIGH TEMPERATURE SHAPE MEMORY PROPERYIES OF TiPdNi ALLOY WITH NEW PRECIPITATE PHASE

新型析出相TiPdNi合金的组织控制及高温形状记忆性能的改善

基本信息

批准号：
12650700
负责人：
NISHIDA Minoru
金额：
$ 2.56万
依托单位：
KUMAMOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12650700/
关键词：
SHAPE MEMORY ALLOY AGING AND PRECIPITATION ORDER-DISORDER TRNSITION THERMOELASTIC MARTENSITIC TRANSFORMATION TRANSMISSION ELECTRON MICROSCOPY ELECTRON DIFFRACTION LONG PERIOD STACKING STRUCTURE ANTIPHASE DOMAIN BOUNDARY TiPdNi合金高温形状記憶合金

项目摘要

Since martensitic transformation temperature of Ti-Pd-Ni alloys can be controlled from ambient temperature to around 800 K by substitutional ratio of Pd and Ni, the application of me alloys have been expected in various fields. To improve the materials properties the microstructure control with precipitation of secondary phase has been attempted in Ti-rich and Pd and Ni-rich alloys.The authors have found out that quenched Ti_<45>Pd_<45>Ni_<10> alloy shows peculiar phase transformations. Upon heating in DSC measurement, an endothermic reaction occurs firstly around 373 K, which corresponds to the reverse martensitic transformation from B19 to B2 structure. Subsequently, a pair of exothermic and endothermic peaks is observed from 550 to 740 K, which is due to the appearance and disappearance of new order phase with long period stacking structure. One of characteristic feature in electron diffraction pattern of the new phase is superlattice spots at 1/8 position in the row of reflections of 111_<B2>*. Finally, an exothermic reaction which corresponds to the formation of Ti_2(PdNi)_3 phase is detected around 850 K. More interesting phenomenon, which is the parent phase stabilization with low temperature aging below 500 K, is discovered. The ω diffuse streak with rather strong intensity is observed in electron diffraction patterns taken from the stabilized B2 phase. It is confirmed that the diffuse streak is a kind of precursor phenomena of the ordering. Morphological and crystallographic aspects of the new order phase are also discussed. The reversible shape memory effect can be generated by using the new order phase. However, the amount of shape change is smaller than that of Ni-rich Ti-Ni alloy with Ti_3Mi_4 precipitates.

由于Ti-PD-Ni合金的马塞西氏菌转化温度可以通过PD和Ni的替代比从环境温度到约800 K控制，因此预计ME合金在各个领域的应用。为了改善材料特性，在富含Ti-pd和Ni富合金中尝试使用次级沉淀的微观结构控制。在DSC测量中加热后，吸热反应首先发生在373 K左右，这对应于从B19到B2结构的反向Martensisitic转化。随后，观察到550至740 K的一对放热和吸热峰，这是由于具有长时间堆叠结构的新阶阶段的外观和消失。新阶段的电子衍射模式中的特征特征之一是在111_ <b2>*反射行中处于1/8位置的超晶格斑点。最后，在850 k左右检测到了对应于Ti_2（PDNI）_3相的形成的放热反应。发现了更有趣的现象，即发现了低温衰老以下500 K的母体相位稳定。在从稳定的B2相中采取的电子衍射模式中观察到具有相当强烈强度的ω漫射条纹。可以证实，弥漫性条纹是订购的一种前体现象。还讨论了新订单阶段的形态和晶体学方面。可逆的形状内存效果可以使用新的订单阶段生成。但是，形状变化的量小于带有Ti_3mi_4沉淀物的富含Ni-Ni-Ti-Ni合金的形状变化量。