Experimental observations on rate-dependent cyclic deformation of super-elastic NiTi shape memory alloy
Experimental observations on rate-dependent cyclic deformation of super-elastic NiTi shape memory alloy
复制标题
超弹性NiTi形状记忆合金速率相关循环变形的实验观察
DOI：
10.1016/j.mechmat.2016.02.011
复制
发表时间：
2016-06-01
影响因子：
3.9
通讯作者：
Yan, Wenyi
中科院分区：
文献类型：
--
作者：
Kan, Qianhua;Yu, Chao;Yan, Wenyi
通过在不同应变速率（3.3 × 10（-4）~ 3.3 × 10（-2）/s）下的应变控制循环拉伸-卸载试验，研究了应变速率对超弹性NiTi形状记忆合金（SMA）单轴循环变形的影响。结果表明，在循环加载过程中，超弹性发生了明显的退化，随着循环次数和应变速率的增加，残余应变和相变硬化增加，而正相变起始应力和最大响应应力减小，并在一定循环次数后达到饱和状态。循环加载过程中，循环耗散能逐渐减小，并在一定循环次数后达到饱和，但循环耗散能并不随应变率的增加而单调变化。此外，由于非弹性耗散和相变潜热产生的内部热量，NiTi形状记忆合金的温度出现了振荡现象，且温度变化幅度随应变率的增加而单调增加，这是NiTi形状记忆合金的率相关循环变形的物理本质。(C)2016爱思唯尔有限公司版权所有
Based on the strain-controlled cyclic tension-unloading tests at various strain rates (3.3 x 10(-4)-3.3 x 10(-2)/s), the effect of strain rate on the uniaxial cyclic deformation of a super-elastic NiTi shape memory alloy (SMA) was investigated. It is concluded that apparent degeneration of super-elasticity occurs during the cyclic loading, i.e., the residual strain and transformation hardening increase, but the start stress of forward transformation and the maximum responding stress decrease with the increasing number of cycles and strain rate, and finally reach to their saturated states after certain cycles. Although the dissipation energy per cycle decreases progressively during the cyclic loading and is saturated after certain cycles, it does not change monotonically with the increasing strain rate. Moreover, the temperature oscillation is observed due to the internal heat production from the inelastic dissipation and transformation latent heat, and the extent of temperature variation increases monotonically with the increasing strain rate, which is the physical nature of rate-dependent cyclic deformation of the NiTi SMA. (C) 2016 Elsevier Ltd. All rights reserved.