Transformation-Induced Creep and Creep Recovery of Shape Memory Alloy.
Transformation-Induced Creep and Creep Recovery of Shape Memory Alloy.
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DOI：
10.3390/ma5050909
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发表时间：
2012-05-22
期刊：
影响因子：
--
通讯作者：
Pieczyska EA
中科院分区：
文献类型：
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作者：
Takeda K;Tobushi H;Pieczyska EA
如果形状记忆合金在应力控制条件下经受子回路加载，则可以基于马氏体相变出现蠕变和蠕变恢复。在形状记忆合金元件的设计中，这些变形特性是重要的，因为形状记忆合金元件的偏转在恒定应力下可以改变。根据形状记忆合金马氏体相变动力学，讨论了马氏体相变进行的条件。在恒定应力速率下加载时，由于应力诱发马氏体相变，温度升高。如果应力在加载过程中的马氏体相变阶段保持恒定，则温度降低并且满足马氏体相变进行的条件，导致相变诱导的蠕变变形。如果在卸载过程的逆相变阶段应力保持不变，则由于逆相变而出现蠕变回复。这些热机械性能的细节进行了实验研究的TiNi形状记忆合金，这是在实际应用中最广泛的。马氏体相的体积分数与蠕变应变的增加成比例地增加。
If the shape memory alloy is subjected to the subloop loading under the stress-controlled condition, creep and creep recovery can appear based on the martensitic transformation. In the design of shape memory alloy elements, these deformation properties are important since the deflection of shape memory alloy elements can change under constant stress. The conditions for the progress of the martensitic transformation are discussed based on the kinetics of the martensitic transformation for the shape memory alloy. During loading under constant stress rate, temperature increases due to the stress-induced martensitic transformation. If stress is held constant during the martensitic transformation stage in the loading process, temperature decreases and the condition for the progress of the martensitic transformation is satisfied, resulting in the transformation-induced creep deformation. If stress is held constant during the reverse transformation stage in the unloading process, creep recovery appears due to the reverse transformation. The details for these thermomechanical properties are investigated experimentally for TiNi shape memory alloy, which is most widely used in practical applications. The volume fraction of the martensitic phase increases in proportion to an increase in creep strain.