Role of severe plastic deformation on the cyclic reversibility of a Ti50.3Ni33.7Pd16 high temperature shape memory alloy
Role of severe plastic deformation on the cyclic reversibility of a Ti50.3Ni33.7Pd16 high temperature shape memory alloy
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DOI：
10.1016/j.actamat.2010.08.003
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发表时间：
2010-11
期刊：
影响因子：
9.4
通讯作者：
B. Kockar;K. Atli;Ji Ma;M. Haouaoui;I. Karaman;M. Nagasako;R. Kainuma
中科院分区：
文献类型：
--
作者：
B. Kockar;K. Atli;Ji Ma;M. Haouaoui;I. Karaman;M. Nagasako;R. Kainuma
研究了等通道转角挤压（ECAE）对Ti50.3Ni33.7Pd16高温形状记忆合金（HTSMA）热机械循环稳定性的影响。高温奥氏体相的晶粒/亚晶粒尺寸细化至约100 nm，这是迄今为止在HTSMA中报道的最低值。ECAE后的转变和宏观塑性屈服之间的强度差的增加导致在等压冷却-加热实验期间的循环稳定性的显着增强。在ECAE过程中，由于显微组织的细化，位错滑移的临界应力增加，从而减少了不可恢复的应变水平。
The present work focuses on the effect of microstructural refinement on the thermo-mechanical cyclic stability of a Ti50.3Ni33.7Pd16high temperature shape memory alloy (HTSMA) which was severe plastically deformed using equal channel angular extrusion (ECAE). The grain/subgrain size of the high temperature austenite phase was refined down to about 100nm, the lowest reported to date in HTSMAs. The increase in strength differential between the onset of transformation and the macroscopic plastic yielding after ECAE led to a notable enhancement in the cyclic stability during isobaric cooling–heating experiments. The reduction in irrecoverable strain levels was attributed to the increase in critical stress for dislocation slip due to the microstructural refinement during the ECAE process.