准静态拉伸过程中CoCrFeMnNi高熵合金显微组织的演变

Microstructure evolution of CoCrFeMnNi high-entropy alloy during quasi-static tensile

采用电子背散射衍射技术,研究室温下CoCrFeMnNi高熵合金在准静态单向拉伸(应变速率为1×10^(-1)s^(-1))过程中显微组织的演变。结果表明:合金的变形机制主要是位错的滑移,同时伴随着少量的孪生。当应变约为0.81%时,合金开始出现新的Σ3孪晶界。晶向<001>附近的拉伸轴向<001>方向转动,形成弱的<001>//RD丝织构,符合Toylor模型,晶粒拉伸轴向<001>-<111>连线转动,符合Sachs模型。晶粒尺寸显著影响晶粒的转动速率,小尺寸晶粒转动最快,大尺寸晶粒次之,中等尺寸晶粒转动最慢。晶粒Schmid因子越大,晶粒的转动越快。

The evolution of microstructure of CoCrFeMnNi high-entropy alloy during quasi-static tensile （strain rate 1×10-1 s-1） were investigated using electron backscatter diffraction technology. The results show that the dominant deformation mechanism is dislocation gliding, which is accompanied with less twinning. The alloy generates new Σ3 twin boundaries when the strains is 0.81%. The tensile axes close to 〈001〉 rotate toward 〈001〉 and form a weak 〈001〉//RD fiber texture following Toylor model. The tensile axes rotate to the line of 〈001〉-〈111〉 following Sachs model, the grain size influences the rotational speed of grains. The rotational speed of small grain is the fastest than big grains and medium grains, and the medium grain is the slowest than other grains. The bigger Schmid factor of grain is, the faster grain rotation is.