【摘要】 针对18CrNiMo7-6合金钢表面变质层的静、动态力学行为表征问题，提出表面变质层（Surface-Modified Layer, SML）Johnson-Cook(J-C)本构模型分层反演方法。将SML进行分层处理，开展了含有不同表面变质层厚度的圆柱试样动态压缩试验；通过递进式参数反演，分别确定了SML各层深处的应变率敏感系数C；结合SML各层深处不同温度准静态薄板拉伸试验，确定了其对应的屈服强度A、应变硬化系数B、应变硬化指数n及热软化指数m。试验结果表明，18CrNiMo7-6合金钢SML呈明显的应变硬化、应变率强化及温度软化效应。此外，建立了J-C本构模型参数与无量纲深度h/h_b（到SML表面的距离/SML有效深度）的关联模型，为后续的复合强化仿真提供支撑。更多还原

【Abstract】 To address the issue of characterizing static and dynamic mechanical behaviors of the surface-modified layer(SML) in 18CrNiMo7-6 alloy steel, a layered inversion method for the Johnson-Cook(J-C) constitutive model of SML was proposed. The SML was subjected to layered processing, and dynamic compression tests were conducted on cylindrical specimens with different SML thicknesses. Through progressive parameter inversion, the strain rate sensitivity coefficient C at each depth of the SML was determined. Combined with quasi-static thin plate tensile tests at different temperatures for each depth of the SML, the corresponding yield strength A, strain hardening coefficient B,strain hardening index n,and thermal softening exponent m were determined. Test results show that the SML of 18CrNiMo7-6 alloy steel exhibits significant strain hardening, strain rate strengthening, and temperature softening effects. Additionally, a correlation model between J-C constitutive parameters and dimensionless depth h/h_b(distance to SML surface/SML effective depth) was established, providing support for subsequent composite strengthening simulations.更多还原