尺寸依赖的CoCrFeNiMn晶体/非晶双相高熵合金塑性变形机制的分子动力学模拟  

Molecular dynamics simulation of size dependent plastic deformation mechanism of CoCrFeNiMn crystalline/amorphous dual-phase high-entropy alloys

作　　者：安敏荣 李思澜 宿梦嘉 邓琼[3] 宋海洋[1,2] An Min-Rong;Li Si-Lan;Su Meng-Jia;Deng Qiong;Song Hai-Yang(College of New Energy,Xi’an Shiyou University,Xi’an 710065,China;College of Materials Science and Engineering,Xi’an Shiyou University,Xi’an 710065,China;School of Aeronautics,Northwestern Polytechnical University,Xi’an 710072,China)

机构地区：[1]西安石油大学新能源学院,西安710065 [2]西安石油大学材料科学与工程学院,西安710065 [3]西北工业大学航空学院,西安710072

出　　处：《物理学报》2022年第24期146-157,共12页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:12072286);陕西省自然科学基金(批准号:2021JZ-53)资助的课题。

摘　　要：晶体/非晶双相高熵合金是近年来研究人员提出的获得高强高韧高熵合金的有效策略,其塑性变形机制和组成相的尺寸密切相关.本文采用分子动力学模拟方法研究了组成相尺寸对CoCrFeNiMn晶体/非晶双相高熵合金塑性变形机制的影响.研究表明,非晶相尺寸对双相高熵合金的力学行为和塑性变形机制有显著影响.对于非晶相厚度较小的样品,塑性变形是位错滑移和面心立方向六方密排结构的相变主导的,尤其是在非晶厚度为1 nm的样品中观察到了孪晶和位错锁;非晶相厚度适中时,双相高熵合金主要通过晶体相中位错滑移、面心立方向六方密排结构的相变和非晶相的剪切带增殖来实现塑性变形;非晶相厚度较大时,双相高熵合金的塑性变形则由非晶相中均匀剪切带的形成主导.此外,非晶相厚度的增加对位错的形核和发射有延迟作用,并且,晶体/非晶双相结构中的非晶相有稳定晶粒的作用.本文的研究结果对于设计和制备高性能的高熵合金具有一定的科学价值和指导意义.Recently proposed crystalline/amorphous dual-phase high-entropy alloy is an effective strategy to obtain high-entropy,high-strength and high-toughness alloys.And the relative plastic deformation mechanism is dependent on the size of component phases.The effect of component phase size on the plastic deformation mechanism of CoCrFeNiMn crystalline/amorphous dual-phase high-entropy alloy is investigated by molecular dynamics simulation.The results indicate that the size of amorphous phase has a significant effect on the mechanical behavior and plastic deformation mechanism of high entropy alloy.For the sample with small thickness of amorphous phase,the plastic deformation is dominated by dislocation slip and phase transformation of face-centered-cubic structure to hexagonal-close-packed structure.Especially,the deformation twins and Lomer-Cottrell locks are observed in the sample with amorphous layer spacing of 1 nm.When the thickness of the amorphous layer is moderate,the plastic deformation of the dual-phase high-entropy alloy is realized mainly through the dislocation slip,phase transformation of face-centered-cubic structure to hexagonalclose-packed structure in crystalline part and shear band multiplication in amorphous part.If the amorphous layer spacing is larger,the plastic deformation of the high-entropy alloy is dominated by the formation of uniform shear bands in the amorphous phase.In addition,the amorphous phase in the dual-phase high-entropy alloy structure can stabilize the crystalline grains.The results of this study can provide a guidance for designing and preparing high entropy alloy with high performance.

关 键 词：晶体/非晶双相高熵合金 尺寸效应 变形机制 分子动力学模拟 

分 类 号：TG139[一般工业技术—材料科学与工程]