微载荷连续球压痕法评价金属材料的屈服强度和应变硬化指数

Yield Strength and Strain Hardening Exponent of Metal Material Evaluated by Micro-load Continuous Ball Indentation Method

对现有球压痕测试材料力学性能的方法进行改进,采用连续循环加载方法代替多点单次加载方法得到金属材料的载荷深度曲线,通过量纲分析和有限元分析拟合出压头压入金属材料过程中的无量纲函数及对应的表观应变函数,并得到不同金属材料的弹塑性参数和应力-应变曲线,通过试验数据对其进行了验证。结果表明:通过该方法计算得到的金属材料弹塑性参数与试验数据的误差均为5%左右,且两者的应力-应变曲线基本吻合。

The method of testing mechanical properties of materials by existing ball indentation was improved and the load-depth curve of metal material was obtained by a continual cycle loading method instead of multipoint single loading method.The dimensionless functions and related apparent strain function during indenter pressing into metal material were fitted by dimensional analysis and finite element anslysis,and the elastic-plastic parameters and stress-strain curves of different metal materials were obtained and verified by the test data.The results show that the error of elastic-plastic parameters between the caculation results obtained by this method and the test data was about 5%.The stress-strain curves were in good agreement.