热处理对冷轧变形Al_(0.3)CoCrFeNi高熵合金组织与力学性能的影响

Effect of heat treatment on microstructure and mechanical properties of Al_(0.3)CoCrFeNi high entropy alloy with cold rolling

利用X射线衍射仪、光学显微镜、扫描电镜、电子背散射衍射、硬度测试和拉伸实验等手段,研究了退火温度对冷轧变形量为95%的Al_(0.3)CoCrFeNi高熵合金微观组织和力学性能的影响。结果表明:合金经过95%冷轧变形后仍保持FCC单相;冷轧变形后的合金的硬度明显提高,塑性大幅下降,强度提高了4~5倍;经过600℃以上温度退火后,合金发生再结晶;随着退火温度的升高,晶粒尺寸逐渐增大,合金强度下降,塑性提高,断口形貌由解理特征向韧窝特征转变;同时在600~800℃退火时合金中有少量第二相(BCC相)析出,温度越高,第二相析出越明显。

The effects of heat treatment on microstructure and mechanical properties of Al_（0.3）CoCrFeNi high entropy alloy after 95% coldrolling were investigated by means of X-ray diffraction,optical microscope,scanning-electronic microscopy,electron back-scattered diffraction technique,hardness test and tensile test.The results show that the Al_（0.3）CoCrFeNi high entropy alloy remains single facecentered cubic（ FCC） crystal structure after 95% cold-rolling.The hardness of the alloy increases obviously and the plasticity decreases greatly,and the strength increases by 4-5 times after 95% cold-rolling.When the subsequent annealing temperature is higher than 600℃,recrystallization occurs.With the increasing of the annealing temperature,the recrystallization grain size increases,the strength of the alloy decreases,the plasticity increases and the fracture morphology changes from dissociative feature to the dimple feature.Meanwhile,a few of second phase（ BCC） with body-centered cubic（ BCC） structure is observed in the alloy annealed at the temperature between 600℃ and 800 ℃ and the precipitation of the second phase becomes more obvious at higher annealing temperature.