基于加工硬化率的新型轻质钢动态再结晶临界条件及变形机制研究  

Study on the Critical Condition and Deformation Mechanism of Dynamic Recrystallization of Novel Lightweight Steel Based on the Work Hardening Rate

作　　者：孙建 黄贞益 李景辉[1,2] 王萍 吴旭明 SUN Jian;HUANG Zhenyi;LI Jinghui;WANG Ping;WU Xuming(School of Metallurgical Engineering,Anhui University of Technology,Maanshan 243002,Anhui,China;China Key Laboratory of Metallurgical Emission Reduction&Resources Recycling,Ministry of Education,Anhui University of Technology,Maanshan 243002,Anhui,China;School of Mechanical Engineering,Tongling University,Tongling 244061,Anhui,China)

机构地区：[1]安徽工业大学冶金工程学院,安徽马鞍山243002 [2]安徽工业大学冶金工程与资源综合利用安徽省重点实验室,安徽马鞍山243002 [3]铜陵学院机械工程学院,安徽铜陵244061

出　　处：《材料导报》2022年第19期162-170,共9页Materials Reports

基　　金：国家自然科学基金(51674004,51805002)。

摘　　要：采用Gleeble3500热模拟实验机,在850~1050℃温度范围内和0.01~5 s^(-1)应变速率范围内,对试验钢进行了等温压缩变形处理,得到试验钢的应力-应变曲线。通过数据处理进一步得到试验钢加工硬化率-应变关系曲线、动态再结晶临界应力和临界应变,并借助OM、TEM及EBSD表征技术,分析了试验钢的组织演化规律和变形机制。结果表明:在相对低温和低应变速率下,随着应变量的增加,由于加工硬化再次占据主导地位,试验钢出现了明显的流动应力“二次增大”现象;随着热变形温度的降低和应变速率的增大,试验钢的峰值应力和临界应力、峰值应变和临界应变都呈现出增大趋势,并得出其相互之间新的关系模型;在变形条件下,试验钢再结晶晶粒尺寸随着温度的升高和应变速率的降低而增大,层错能(SFE)值随着变形温度的升高而增大,范围为181.1~237.4 mJ/m^(2),试验钢热变形后组织中有孪晶存在,说明SFE并非是影响高锰奥氏体钢变形机制的唯一因素,试验钢的主要变形机制为位错滑移。In this work,the stress-strain curves of the experimental steel were obtained after isothermal compression deformation within the temperature 850—1050℃of and the strain rate of 0.01—5 s^(-1) on Gleeble3500 thermal-mechanical simulator.The work hardening rate-strain curves,dynamic recrystallization critical stress and critical strain of the experimental steel were further obtained by data processing.The microstructures evolution and deformation mechanism of the experimental steel were analyzed by OM,TEM and EBSD.The results show that for the experimental steel,there is an obvious‘secondary increase’phenomenon of the flow stress,for the the dominant position is occupied again by work hardening as the strain increases at relatively low temperature and low strain rate.The peak stress,critical stress,peak strain and critical strain of the experimental steel show an increasing trend,as the deformation temperature decreases and the strain rate increases,and simultaneously,a new relationship model between them is obtained.The recrystallization grain size of the experimental steel increases with the increase of temperature and the decrease of strain rate,and the stacking fault energy(SFE)ranges from 181.1 mJ/m^(2) to 237.4 mJ/m^(2),which exhibits increasing trend with the increase of temperature under the deformation condition.It can be concluded that stacking fault energy is not the only factor affecting the deformation mechanism of the experimental steel because of the presence of the twins after hot deformation of the experimental steel.Dislocation slipping is the main deformation mechanism of the experimental steel.

关 键 词：轻质钢 等温压缩 加工硬化率 动态再结晶 变形机制 

分 类 号：TG142.1[一般工业技术—材料科学与工程]