高强塑积Q&P钢中的残留奥氏体演变规律及力学性能  

Evolution law of retained austenite and mechanical properties of high strength-ductility Q&P steel

作　　者：刘晓明 李辉[1] 吴冰冰 张笛 周书豪 LIU Xiao-ming;LI Hui;WU Bing-bing;ZHANG Di;ZHOU Shu-hao(School of Materials Science and Engineering,Shandong University of Technology,Zibo 255000,China;Scientific Research Office,Yantai Nanshan University,Yantai 265713,China)

机构地区：[1]山东理工大学材料科学与工程学院,山东淄博255000 [2]烟台南山学院科研处,山东烟台265713

出　　处：《材料热处理学报》2024年第12期150-158,共9页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(52274384)。

摘　　要：采用场发射扫描电镜(SEM)、电子背散射衍射(EBSD)和X射线衍射仪(XRD)等研究了不同淬火制度、配分制度对高强塑积Q&P钢显微组织演变的影响;利用万能拉伸试验机测试了其力学性能;基于数学模型预测了最优工艺下不同强化机制对屈服强度的贡献;表征了变形过程中残留奥氏体的相变诱导塑性(TRIP)效应。结果表明:淬火温度为200℃时,试验Q&P钢的马氏体组织较细小,残留奥氏体含量较多;经200℃淬火+300℃×3 min配分处理后,变形过程中能充分地发挥TRIP效应,获得最佳的综合力学性能,强塑积达到22.67 GPa·%;变形过程中,80%的残留奥氏体在15%应变前发生了TRIP效应,有助于均匀塑性变形;仅有约10%的残留奥氏体在15%~20%的应变区间发生TRIP效应,产生颈缩直至断裂;残留奥氏体的稳定性和数量共同决定了TRIP效应的强弱。Effects of different quenching and distribution processes on microstructure evolution of high strength-ductility Q&P steel were studied using field emission scanning electron microscopy(SEM),electron backscatter diffraction(EBSD)technique and X-ray diffraction(XRD),and its mechanical properties were tested using a universal tensile testing machine.Based on mathematical models,the contribution of different strengthening mechanisms to yield strength under the optimal heat treatment process was predicted.The phase transformation induced plasticity(TRIP)effect of retained austenite during deformation was characterized and analyzed.The results show that when the quenching temperature is 200℃,the martensitic structure of the experimental Q&P steel is relatively small,and the retained austenite content is relatively high.After quenching at 200℃and partitioning at 300℃for 3 min,the TRIP effect can be fully utilized during the deformation,achieving the best comprehensive mechanical properties,with a product of strength and plasticity of 22.67 GPa·%.During the deformation,80%of the retained austenite undergoes TRIP effect before 15%strain,which helps to achieve uniform plastic deformation.Only about 10%of the retained austenite undergoes TRIP effect in the strain range of 15%to 20%,leading to necking and fracture.Therefore,the intensity of the TRIP effect is dependent on both the stability and quantity of the retained austenite.

关 键 词：Q&P钢 残留奥氏体 力学性能 数学模型 TRIP效应 

分 类 号：TG142.3[一般工业技术—材料科学与工程]