NiTi形状记忆合金热弹性马氏体相变的分子动力学模拟  

Molecular Dynamics Simulation of Thermoelastic Martensitic Transformation in NiTi Shape Memory Alloy

作　　者：彭淼 马莹 邓聪颖 赵洋 陈翔 PENG Miao;MA Ying;DENG Congying;ZHAO Yang;CHEN Xiang(Chong Machinery&Electronics Equipment Technology Research Academy,Chongqing 401123,China;Chongqing University of Posts and Telecommunications Advanced Manufacturing Institute,Chongqing 400065,China)

机构地区：[1]重庆机电装备技术研究院有限公司,重庆401123 [2]重庆邮电大学先进制造工程学院,重庆400065

出　　处：《材料科学与工程学报》2020年第5期840-846,共7页Journal of Materials Science and Engineering

基　　金：国家自然科学基金青年基金资助项目(11802047,51705058,51807019);国家自然科学基金应急管理项目资助项目(11647101);重庆市科学技术委员会资助项目(cstc2016jcyjA0594);重庆市教育委员会资助项目(KJ1600446)。

摘　　要：利用分子动力学方法,基于2NN-MEAM势函数对<001>晶向NiTi单晶的热力学行为进行模拟。再现了温度诱发马氏体相变并确定NiTi单晶的四个特征相变温度。根据特征相变温度分别对马氏体状态的重取向变形,奥氏体态的形状记忆效应以及奥氏体状态的伪弹性响应进行模拟。发现温度诱发的马氏体相变形成了多个不同取向的自协调马氏体变体,从原子尺度动态再现施加应力诱发马氏体重取向时,温度诱发的有利取向变体在载荷作用下吞噬不利取向变体完成重取向过程;在较高温度预测了NiTi合金的形状记忆效应和伪弹性,随着温度的升高应力诱发相变所需的驱动力越大。本研究的分子动力学计算结果所得的规律性认识与实验结果和理论预测一致,弥补了实验和理论方面研究的不足。The thermodynamic behavior of<001>crystalline direction of NiTi single crystal is simulated based on molecular dynamics(MD)method using the 2NN-MEAM potential function.Temperature induced martensitic transformation is simulated to determine the four characteristic transformation temperatures.The martensitic reorientation deformation,the effect of shape memory on austenite and its pseudoelastic behavior are also simulated,respectively.The simulation results indict that self-coordination martensite variants with multiple different orientations are generated by temperature-induced martensitic transformation.For the first time,such a process is reproduced dynamically from the atomic scale,i.e when martensitic reorientation occurs via applied stress,the unfavorable disorientation variants are devoured by the favorable temperature-induced martensite variants throughout the reorientation process.Second,the shape memory effect of NiTi alloy and its pseudoelasticity are numerically predicted at relative higher temperature.It is discovered that the driving force needed for stress-induced phase transformation increases with the increase of the temperature.The mechanism recognition derived from molecular dynamics simulation is consistent with macro-and micro-scale experimental results and theoretical predictions.This research validates the MD simulation method and makes up for the lack of experimental and theoretical research through dynamic microstructural evolution prediction.

关 键 词：NITI合金 分子动力学模拟 马氏体重取向 形状记忆效应 伪弹性 

分 类 号：TG139.[一般工业技术—材料科学与工程]