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总览 评价 董诗玉 , 阚前华 * , 杨强军 , 康国政 ( 西南交通大学力学与工程学院,成都 610031; ) 摘要: 对镍钛形状记忆合金在不同保持时间下的循环变形行为进行了实验研究。结果表明:循环加载下,峰值和谷值载荷保持会促进材料持续发生相变和逆相变
董诗玉, 阚前华*, 杨强军, 康国政
(
西南交通大学力学与工程学院,成都 610031; )
摘要:
对镍钛形状记忆合金在不同保持时间下的循环变形行为进行了实验研究。结果表明:循环加载下,峰值和谷值载荷保持会促进材料持续发生相变和逆相变,峰值保持时间越长,峰值应变越大,耗散能越大;峰值保持时间对残余应变的演化影响不大;进而有谷值保持时间比没有谷值保持时间的峰值应变、残余应变和耗散能都大。发生在保持时间内的相变应变随循环周次的增加逐渐减小,随保持时间的增加而增加。当加载的峰值应力接近相变结束应力时,保持时间的增加对马氏体相变的促进作用相对微弱。
关键词:
形状记忆合金;保持时间;马氏体相变;应力循环
Dong Shiyu, Kan Qianhua*, Yang Qiangjun, Kang Guozheng
(
School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031; )
Abstract:
The effect of holding time on cyclic deformation behavior of NiTi shape memory alloy (SMA) was experimentally studied. It is shown from experimental results that loading hold in peak and valley can promote phase transformation of SMA, peak strain and dissipation energy increase with an increased peak hold time; however, peak hold time has a little influence on the evolution of the residual strain. Moreover, a valley holding time can produce more peak strain, residual and dissipation energy than those of without holding time. The strain increment occurring in holding time decreases and increases with an increased number of cycles and holding time, respectively. When loading peak stress approaches the finish value of transformation stress, an increased hold time has a weak promotion on martensite phase transformation.
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