获取材料弹性模量和硬度的压痕功改进方法研究

Study of an Improved Indentation Energy Method for Obtaining Elastic Modulus and Hardness of Materials

采用Oliver-Pharr(OP)法计算材料的弹性模量和压痕硬度时,其精度与卸载斜率和残余压痕深度的计算精度直接相关。为减小卸载斜率和残余压痕深度对OP法的影响,根据量纲分析理论和Π定理,建立了残余压痕深度、弹性模量和压痕硬度与被测材料性能和压痕参数之间的无量纲函数关系。采用有限元仿真分析,获得了3个无量纲函数的解析表达式。压痕试验结果表明:通过改进的压痕功法有效避免了试验误差、计算误差和人为因素等对卸载斜率和残余压痕深度的影响,提高了弹性模量和压痕硬度计算的精度。

The accuracy of elastic modulus and indentation hardness using the Oliver-Pharr method is seriously affected by the calculation accuracy of the unloading slope and residual indentation depth. Based on the dimension analysis theory and II theorem, the dimensionless function relationship was es-tablished among residual indentation depth, elastic modulus, indentation hardness and material proper-ties, indentation parameters to reduce the influence of unloading slope and residual indentation depth on the OP method. Then, three dimensionless analytic expressions were obtained using the finite ele-ment analysis. The results of indentation experiments show that the improved indentation energy meth-od effectively avoid the influence of the experimental error, calculation error and human factors on the unloading slope and residual indentation depth, and improve the calculation accuracy of elastic modu-lus and indentation hardness