基于纳米压痕和有限元模拟的激光熔覆316L不锈钢弹塑性能研究

Nano-indentation and finite element simulation study on the elastic-plastic properties of 316L stainless steel by laser cladding

分别对激光熔覆316L不锈钢涂层、热轧316L不锈钢进行纳米压痕试验得到载荷-位移曲线和弹性模量,并对热轧316L不锈钢进行单轴拉伸试验,以此应力应变曲线作为材料属性,通过有限元模拟纳米压痕,得出载荷-位移曲线,与试验进行比较,验证有限元模型的可靠性。对未知属性的316L熔覆层,选取不同的屈服强度(250~375 MPa)和应变硬化指数(0.25~0.375),正交组合分别模拟,通过与试验结果的对比,得出316L熔覆层屈服强度为325 MPa,应变硬化指数为0.3,并分析了载荷-位移曲线参量随材料属性的变化规律。

The load-displacement curves and elastic modulus of laser cladding 316 L stainless steel coating and hot rolled 316 L stainless steel were obtained by nano-indentation test. And the uniaxial tensile test of hot rolled 316 L stainless steel was carried out. Based on the stress-strain curve,the load-displacement curve was obtained by finite element simulation of nano-indentation. The reliability of the finite element model was verified by comparing with the experimental results. For unknown material properties of 316 L cladding layer,different yield strengths（ 250-375 MPa） and strain hardening exponents（ 0. 25-0. 375） were selected for simulation by orthogonal combination. By comparing with the experimental results,the yield stress of 325 MPa and value of 0. 3 for the strain hardening exponent were obtained for 316 L cladding layer. And the variation law of load-displacement curves with material property was analyzed.