高温固相扩散处理对开孔泡沫Fe-Ni力学性能的影响

采用高温固相扩散处理对开孔泡沫Fe-Ni进行合金化,研究了不同处理温度,不同保温时间对泡沫Fe-Ni压缩性能及能量吸收特性的影响。采用扫描电镜(SEM)对合金化后的泡沫Fe-Ni进行形貌观察,并利用线扫描分析合金化前后两种元素的扩散情况;对合金化前后的泡沫Fe-Ni进行了纳米压痕试验和准静态压缩试验,研究了泡沫Fe-Ni网丝硬度、准静态压缩力学行为及其吸能性。结果表明:经高温固相扩散处理后,泡沫Fe和Ni镀层界面上发生了Fe-Ni的互扩散,形成(Fe,Ni)无限固溶体结构;随着温度升高,保温时间增长,Fe、Ni元素分布更趋于均匀化,泡沫Fe-Ni网丝平均纳米硬度值更高。1200℃高温固相扩散2h后泡沫Fe-Ni平台区应力值增加,平台区长度增加。泡沫Fe-Ni吸能能力整体趋势随应变的增加而线性增大。其中,1200℃高温固相扩散保温2h,泡沫Fe-Ni能量吸收值比合金化前提高了31.9%。

Effect of the Solid Phase Diffusion on the Mechanical Properties of Open-Cell Fe-Ni Alloy Foams

The open-cell Fe-Ni foams were alloyed by solid phase diffusion at high temperature. The compression performance and energy absorption characteristics of open-cell Fe-Ni alloy foams were investigated at different temperatures and for different holding times. The microstructure and the elemental analysis of open-cell Fe-Ni alloy foams were investigated using scanning electron microscopy (SEM) and energy spectrum diffraction (EDS) The mechanical properties and energy absorption of the open cell Fe-Ni foams were examined by compressive testing at room temperature. It is found that after homogenization at 1100 and 1200 ℃, the interdiffusion occurred at Fe-Ni interface, and a (Fe, Ni) solid solution was formed. With the temperature and holding time increasing, the average nanohardness values of foam mesh are increased, and the Fe and Ni concentration gradients along the strut thickness are removed and show uniform distribution. The plateau stress and plateau length of the Fe-Ni foams are increased at 1200 ℃ for 2 h. The energy absorption of Fe-Ni alloyed foam is increased linearly. The energy absorption by unit volume of Fe-Ni alloyed foam is increased by 31.9% at 1200 ℃ for 2 h compared with that of unalloyed Fe-Ni foam.