Study of martensitic stabilisation under stress in Cu–Al–Be shape memory alloy single crystal
Study of martensitic stabilisation under stress in Cu–Al–Be shape memory alloy single crystal
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DOI：
10.1016/j.msea.2003.11.069
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发表时间：
2004-07
期刊：
影响因子：
6.4
通讯作者：
C. Gonzalez;C. Araújo;N. F. Quadros;G. Guénin;M. Morin
中科院分区：
文献类型：
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作者：
C. Gonzalez;C. Araújo;N. F. Quadros;G. Guénin;M. Morin
铜基形状记忆合金中的马氏体稳定化现象总是与形变热处理和淬火后历史有关。这种现象降低了形状记忆性能，降低了其工业应用的潜力。在本工作中，实现了铜铝铍合金单晶的超弹性实验，以研究马氏体的稳定化过程。在一种可以同时测量应力-应变和电阻的专用装置上对直接淬火样品进行了研究。采用了两种实验程序：超弹性循环(8%应变)和混合状态下的老化。在第二次试验中，通过超弹性使样品承受4%的应变，这导致了由平行界面分隔的β相和单一变种马氏体的混合物。24小时后，样品应变高达8%，最后应力被去除，导致总应变恢复。马氏体态时效后的体积分数与β相态时效后的体积分数的应力-应变曲线和电阻率曲线表现出明显不同的行为。从热处理影响和稳定化过程两个方面对结果进行了讨论。
Martensitic stabilisation phenomenon in the copper-based shape memory alloys has been invariably related to thermomechanical treatments and post-quench history. This phenomenon degrades shape memory properties and reduces their potential for industrial applications. In the present work, superelastic tests in a single crystal of Cu–Al–Be alloy were realised to study the martensitic stabilisation processes. Direct quenched samples have been studied in a special apparatus which allows to measure simultaneously stress–strain and electrical resistance. Two experimental procedures were used: superelastic cycles (8% strain) and ageing in mixed state. In the second test, the sample is submitted to a 4% strain by superelasticity which leads to a mixture of β-phase and single variants of martensite separated by parallel interfaces. After 24h, the sample is strained up to 8% and finally the stress is removed leading to a total strain recovery. The stress–strain as well as the resistivity curves show a very different behaviour between the volume fraction which have been aged in the martensitic state and the one aged in the β-phase state. The results are discussed in terms of thermal treatment influence and stabilisation processes.