Shape memory characteristics of Ti49.5Ni25Pd25Sc0.5 high-temperature shape memory alloy after severe plastic deformation
Shape memory characteristics of Ti49.5Ni25Pd25Sc0.5 high-temperature shape memory alloy after severe plastic deformation
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DOI：
10.1016/j.actamat.2011.04.009
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发表时间：
2011-07
期刊：
影响因子：
9.4
通讯作者：
K. Atli;I. Karaman;R. Noebe;A. Garg;Y. Chumlyakov;I. Kireeva
中科院分区：
文献类型：
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作者：
K. Atli;I. Karaman;R. Noebe;A. Garg;Y. Chumlyakov;I. Kireeva
对Ti49.5Ni25Pd25Sc0.5高温形状记忆合金进行热机械处理，以获得增强的形状记忆特性：特别是在恒定载荷下重复热循环时的尺寸稳定性。这是通过等通道转角挤压（ECAE）和后处理退火热处理使用严重的塑性变形来实现的。热机械实验的结果表明，加工后的材料显示增强的形状记忆响应，表现出更高的可恢复的转变和减少的不可恢复的应变水平，热循环时相比，未加工的材料。这种改进是由于增加的强度和电阻的材料对缺陷的产生时，相变作为由于ECAE过程的微观结构细化的结果，如支持的电子显微镜观察。
A Ti49.5Ni25Pd25Sc0.5high-temperature shape memory alloy is thermomechanically processed to obtain enhanced shape-memory characteristics: in particular, dimensional stability upon repeated thermal cycles under constant loads. This is accomplished using severe plastic deformation via equal channel angular extrusion (ECAE) and post-processing annealing heat treatments. The results of the thermomechanical experiments reveal that the processed materials display enhanced shape memory response, exhibiting higher recoverable transformation and reduced irrecoverable strain levels upon thermal cycling compared with the unprocessed material. This improvement is attributed to the increased strength and resistance of the material against defect generation upon phase transformation as a result of the microstructural refinement due to the ECAE process, as supported by the electron microscopy observations.