泡沫镍力学性能的实验研究

本研究在室温下控制位移,先以5mm/min的位移速度对泡沫镍进行了单轴拉伸、压缩实验,然后在不同应变率情况下进行了一系列单轴拉伸实验,得到了相应的应力-应变曲线,讨论了材料的应变率相关性.结果表明在普通拉伸试验范围内(准静态),改变变形速度会影响应力-应变曲线,屈服应力、强度极限随变形速度增大而下降;单轴拉伸时,应力应变关系明显分为线弹性变形、塑性变形、线性硬化和破坏4个阶段;单轴压缩时,具备其他泡沫材料受压典型应力-应变曲线的3阶段特征,即明显的弹性变形段、屈服平台段和紧实段.

An Experimental Study on Mechanical Properties of Nickel Foams

In this study, uniaxial tension and compression tests of nickel foam at a constant deformation rate of 5mm/min were performed at room temperature, and a series of uniaxial tension tests at different strain rates were also conducted, in which corresponding stress-strain curves were obtained,and the strain rate correlation of this material was discussed, too. The results show that within the range of normal tension test (quasi-static state) deformation rate has an effect on stress-strain curve, and yield stress and limit strength drop with increase in deformation rate. Apparently, the stress-strain curve of uniaxial tension consists of four distinct segments:linear elastic deformation, plastic deformation, linear hardening and rupture,and stress-strain curve of uniaxial compression was similar to that of other porous materials which are characterized by three distinct regions: an elastic deformation region, a collapse plateau region and a densification region.