孪晶界对Cr_(26)Mn_(20)Fe_(20)Co_(20)Ni_(14)高熵合金力学行为影响的分子动力学模拟  

Effect of twin boundary on mechanical behavior of Cr_(26)Mn_(20)Fe_(20)Co_(20)Ni_(14) high-entropy alloy by molecular dynamics simulation

作　　者：申天展 宋海洋[1] 安敏荣 Shen Tian-Zhan;Song Hai-Yang;An Min-Rong(College of Materials Science and Engineering,Xi’an Shiyou University,Xi’an 710065,China)

机构地区：[1]西安石油大学材料科学与工程学院,西安710065

出　　处：《物理学报》2021年第18期246-254,共9页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:11572259);陕西省自然科学基金重点项目(批准号:2021JZ-53);西安石油大学《材料科学与工程》省级优势学科项目(批准号:YS37020203);西安石油大学研究生创新与实践能力培养计划(批准号:YCS19211011)资助的课题.

摘　　要：高熵合金突破了传统合金的组成框架,呈现出独特而优越的力学性能.然而,作为合金家族近年来出现的新成员,高熵合金的潜在变形机制亟需进一步揭示.本文采用分子动力学模拟方法研究了纳米孪晶Cr_(26)Mn_(20)Fe_(20)Co_(20)Ni_(14)高熵合金在拉伸载荷下的力学性能,从原子水平揭示了孪晶界对纳米孪晶Cr_(26)Mn_(20)Fe_(20)Co_(20)Ni_(14)高熵合金变形行为的影响.研究结果表明,纳米孪晶Cr_(26)Mn_(20)Fe_(20)Co_(20)Ni_(14)高熵合金的屈服强度随着孪晶界间距的减小而增大,呈现Hall-Petch关系.然而,孪晶界间距存在一个临界值,使得高熵合金的屈服强度在该值前后对孪晶界间距的敏感度发生了明显改变.研究指出,随着孪晶界间距的减小,纳米孪晶Cr_(26)Mn_(20)Fe_(20)Co_(20)Ni_(14)高熵合金的变形机制发生了从以位错滑移主导到以非晶化相变为主的转变.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参考价值和指导意义.The high-entropy alloys break through the traditional alloy structure and present unique and superior mechanical properties.However,the potential deformation mechanism of high-entropy alloy,which is regarded as a new member of alloy families in recent years,needs to be further investigated.In this paper,the mechanical properties of the nano-twin Cr_(26)Mn_(20)Fe_(20)Co_(20)Ni_(14) high-entropy alloy under tensile loading are studied by molecular dynamics simulation,and the effect of twin boundary on the deformation behavior of nano-twin Cr_(26)Mn_(20)Fe_(20)Co_(20)Ni_(14) high-entropy alloy is studied on an atomic level.The results show that the yield strength of the nano-twin Cr_(26)Mn_(20)Fe_(20)Co_(20)Ni_(14) high-entropy alloy increases with twin boundary spacing decreasing,presenting a Hell-Petch relationship.However,there is a critical value of the twin boundary spacing,which makes the sensitivity of the yield strength of the high-entropy alloy to the twin boundary spacing change significantly before and after this value.The results also indicate that the deformation mechanism of nano-twin Cr_(26)Mn_(20)Fe_(20)Co_(20)Ni_(14) high-entropy alloy changes from dislocation slip to amorphous phase transition with the decrease of twin boundary spacing.The research results of this paper have a certain reference value and guidance significance for designing and preparing high-performance high-entropy alloys.

关 键 词：高熵合金 分子动力学模拟 力学行为 孪晶界 

分 类 号：TG139[一般工业技术—材料科学与工程]