应变速率对热冲压淬火-配分钢显微组织与力学性能的影响  

Effect of strain rate on microstructure and mechanical properties of hot stamping quenching-partitioning steel

作　　者：吴聪 景财年[1] 林涛 叶道珉 雷启腾 WU Cong;JING Cainian;LIN Tao;YE Daomin;LEI Qiteng(School of Materials Science and Engineering,Shandong Jianzhu University,Jinan 250101,China)

机构地区：[1]山东建筑大学材料科学与工程学院,济南250101

出　　处：《材料工程》2022年第10期73-79,共7页Journal of Materials Engineering

基　　金：国家自然科学基金面上项目(51871136);济南市高校科研带头人项目(2018GXRC025);山东省重点研发计划(2019GGX104057,2019JMRH0306)。

摘　　要：采用分离式Hopkinson压杆对热冲压淬火-配分(HS-Q&P)钢在0~12000 s^(-1)应变速率范围内进行动态压缩实验,利用SEM,EBSD,XRD等分析表征手段探究动态压缩过程中试样的变形行为。结果表明:实验钢在不同速率下的变形行为基本相似且分为3个阶段,在平台处应力有小幅度增加,增幅更多体现在应变上。在压缩过程中出现的绝热升温会带来软化效应。残余奥氏体的存在会提高实验钢的强度和塑性变形能力。钢中残余奥氏体发生相变诱导塑性(transformation induced plasticity,TRIP)效应减少的体积分数与马氏体增加的体积分数基本一致,证明TRIP效应为钢中主要的强化机制。同时,通过SEM可观测到残余奥氏体发生TRIP效应转变成细小针状马氏体,随着应变速率增加,晶格畸变越来越严重,EBSD图像中可以观测到部分形变孪晶,在不同应变速率下,〈001〉取向的晶粒都会更容易产生形变孪晶。A split Hopkinson pressure bar was used to perform dynamic compression experiments on HS-Q&P steel at the strain rates of 0-12000 s^(-1).The deformation behavior of the specimen during dynamic compression was studied by SEM,EBSD,XRD characterization methods.The results show that the deformation behavior of the experimental steel at different rates is similar and is divided into three stages.First,there is a slight increase in stress at the platform,but the increase is more reflected in the strain.The adiabatic heating effect that occurs during the compression process will bring a softening effect.The strength and plastic deformation ability of the experimental steel can be improved by the retained austenite.The volume fraction of retained austenite in steel reduced by the transformation induced plasticity(TRIP)effect is the same as the volume fraction of martensite increased and proves the TRIP effect is the main strengthening mechanism in the steel.At the same time,it is observed by SEM that the retained austenite is transformed into acicular martensite by the TRIP effect.As the strain rate increases,the lattice distortion becomes more and more serious,and some deformation twins can be observed in the EBSD maps.At different strain rates,〈001〉oriented grains are more likely to produce deformation twins.

关 键 词：热冲压淬火-配分钢 残余奥氏体 应变速率 绝热升温 

分 类 号：TG142.1[一般工业技术—材料科学与工程]