基于纳米压痕逆算法的热冲压马氏体/贝氏体双相组织的微观力学性能  

Micromechanical Properties of Duplex Microstructure of Martensite/Bainite in Hot Stamping via the Reverse Algorithms in Instrumented Sharp Indentation

作　　者：朱彬[1] 杨兰 刘勇[1] 张宜生[1] ZHU Bin;YANG Lan;LIU Yong;ZHANG Yisheng(State Key Laboratory of Materials Processing and Die&Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]华中科技大学,材料科学与工程学院,材料成形与模具技术国家重点实验室,武汉430074

出　　处：《金属学报》2022年第2期155-164,共10页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.U1760205。

摘　　要：为研究高强度钢热冲压后微观组织(尤其是多相微观组织)的力学性能及本构关系,首先通过控制冲压时的模具温度和保压时间获得包含全马氏体、全贝氏体以及马氏体/贝氏体混合组织的试件。然后利用纳米压痕实验获得不同微观组织的载荷-位移曲线,并采用纳米压痕逆算法进行量纲分析计算出上述微观组织的弹性模量、屈服强度、应变硬化指数等力学性能参数,获得不同组织的弹塑性幂强化本构模型。最后通过对应纳米压痕实验过程的有限元模拟,对所获得的本构模型进行校验。结果表明,采用逆算法求得的本构模型可以准确地描述高强度钢热冲压后主要微观组织的力学性能。Lightweight automobiles have a lower impact on the environment and save energy;therefore,they have become a focus within the automobile industry.Hot stamping parts made of high-strength steel have been widely used in car bodies.To study the mechanical properties and constitutive model of high-strength steel after hot stamping,the samples containing full martensite,full bainite,and martensite/bainite dual phases structure were obtained by controlling the tool’s temperature and holding time during hot stamping.Then the load-displacement curves of different microstructures were obtained using nanoindentation tests.Subsequently,the modulus of elasticity,yield stress,strain hardening exponent,and other mechanical properties of these microstructures were calculated by reverse algorithms using dimensional analysis.Further,the power-law elastoplastic constitutive models of different microstructures were derived using these parameters.The errors of yield strength obtained using the reverse algorithm and tensile tests in full martensite and full bainite samples are-1.15%and 3.38%,respectively.The yield strength of the martensitic/bainite sample obtained using the reverse algorithm is 16.62%,24.17%,and-11.78%different from that obtained by the tensile test,showing that the mechanical properties are different under macroscopic and microscopic conditions to some extent.Simultaneously,the average yield strength of the three points is only-1.41%different from that obtained using the tensile test.Finally,the derived constitutive models were verified by simulating the finite element nanoindentation.The results show that the constitutive model obtained using the inverse algorithm can accurately describe the mechanical properties of the main microstructures of high-strength steel after hot stamping.

关 键 词：纳米压痕 逆算法 热冲压 马氏体 贝氏体 微观力学性能 

分 类 号：TG142.1[一般工业技术—材料科学与工程]