Hysteretic and anhysteretic tensile stress–strain behavior of Ni–Fe(Co)–Ga single crystal: Experiment and theory
Hysteretic and anhysteretic tensile stress–strain behavior of Ni–Fe(Co)–Ga single crystal: Experiment and theory
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DOI：
10.1016/j.actamat.2013.11.064
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发表时间：
2014-03
期刊：
影响因子：
9.4
通讯作者：
A. Kosogor;V. L'vov;V. Chernenko;E. Villa;J. Barandiaran;T. Fukuda;T. Terai;T. Kakeshita
中科院分区：
文献类型：
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作者：
A. Kosogor;V. L'vov;V. Chernenko;E. Villa;J. Barandiaran;T. Fukuda;T. Terai;T. Kakeshita
本文测量了单晶Ni-Fe（Co）-Ga形状记忆合金在不同温度下拉伸时的可恢复应变。在马氏体相变温度TM ≥ 200 K以上观察到两种不同的变形过程。一个不寻常的无滞后应力-应变行为的特点是一个巨大的（约14%）的非线性变形被发现高于320 K，而应力-应变曲线显示出明显的滞后在此温度以下。利用铁弹相变的理论应力-温度图解释了磁滞的突然减小。结果表明，当变形合金的温度超过相图中相变线端点所对应的临界值时，可以发生这种几乎无滞后的变形。理论分析表明，在临界温度以上，一个非常小的残余滞后（~ 1 MPa）可能是由于在变形循环中晶体缺陷的重新配置造成的。
Recoverable strains have been measured in a single-crystalline Ni–Fe(Co)–Ga shape memory alloy in the course of tensile tests performed at different temperatures. Two substantially different types of deformation process were observed above the martensitic transformation temperature,TM≈ 200 K. An unusual anhysteretic stress–strain behavior characterized by an enormous (∼14%) nonlinear deformation was found above 320 K, while stress–strain loops showing a pronounced hysteresis were obtained below this temperature. A sudden reduction of hysteresis was explained using the theoretical stress–temperature diagram of ferroelastic phase transitions. It has been shown that this almost anhysteretic deformation can occur when the temperature of the deformed alloy exceeds the critical value corresponding to the endpoint of the phase transition line in the phase diagram. A theoretical analysis showed that above the critical temperature a very small residual hysteresis (∼1 MPa) may be caused by the reconfiguration of crystal defects during the deformation cycle.