基于纳米压痕反向分析的Fe-32Ni超因瓦合金介观尺度弹塑性本构关系

Mesoscale elastic-plastic constitutive relationship of Fe-32Ni super-invar alloy based on nanoindentation inverse analysis

采用纳米压痕技术和电子背散射衍射分析技术对Fe-32Ni超因瓦合金不同取向的晶粒进行了测试,得到了材料在(001)、(101)和(111)取向下的弹性模量和硬度。同时基于量纲分析提出了一种改进的反向算法,并结合有限元仿真对Fe-32Ni超因瓦合金的纳米压痕过程进行了反向分析和计算,通过纳米压痕实验曲线与仿真曲线的对比,最终获得材料在(001)、(101)和(111)取向下的应力应变关系,结果表明:(001)取向下晶粒的屈服强度最高,(101)取向下晶粒的屈服强度最低。此外,(101)和(111)取向的晶粒屈服后的应力-应变曲线变化趋势较为一致,而(001)取向下的应力-应变曲线变化较为平缓,材料在不同取向下的力学响应具有明显的各向异性。

The nanoindentation technique and electron backscattered diffraction(EBSD)technique were used to test the grains with different orientations of Fe-32Ni super-invar alloy to obtain the elastic modulus and hardness of the material in(001),(101)and(111)orientations.An improved inverse algorithm was proposed based on the magnitude analysis.The inverse analysis and calculation of the nanoindentation process of Fe-32Ni super-invar alloy were carried out combined with finite element simulation.The stress and strain relationships of the material in(001),(101)and(111)orientations were finally obtained by comparing the nanoindentation experimental curves with the simulation curves.The results show that the yield strength of the grain in(001)orientation is the highest and the yield strength of the grain in(101)orientation is the lowest.In addition,the stress-strain curves of the grains in(101)and(111)orientations are consistent after yield,while the stress-strain curves of the grains in(001)orientation change gently.The mechanical response of the material in different orientations shows obviously anisotropy.