针对材料弹性模量仪器化压入识别的两种代表性方法———Ma方法和Oliver-Pharr方法,应用有限元数值模拟,分析了金刚石压头与具有典型加工硬化特性的金属类被测材料之间接触面摩擦系数对弹性模量识别精度的影响,分析结果表明:摩擦系数介于0~0.2范围时,采用两种方法,弹性模量识别精度对摩擦系数的变化较敏感;摩擦系数大于0.2之后,两种方法对摩擦系数变化的敏感性降低,弹性模量的识别精度趋于稳定。对两种方法的测试精度进行比较可以看出,Ma方法测试结果的精度和相对于摩擦系数变化的稳定性均好于Oliver-Pharr方法,仪器化压入实验应使用Ma方法识别材料的弹性模量。两种铝合金材料的实验数据表明,将摩擦系数对测试结果的影响进行修正,可有效提高Oliver-Pharr方法弹性模量的识别精度。

Frictional effects on instrumented indentation of strain hardening solids were examined. Finite-element simulations were carried out to study the effects of friction coefficient on the two representative indentation test methods: Ma method and Oliver-Pharr method. It is found that for different friction coefficient from 0 to 0.2, the test accuracy of elastic modulus derived by Ma method or Oliver-Pharr method is evidently sensitive to the values of friction coefficient; While the friction coefficient is > 0.2, the sensitivity of test accuracy tends to be stable. Comparing the test accuracy of the two methods, Ma method are better than Oliver-Pharr method in terms of test accuracy and stability. Ma method is recommended for instrumented indentation test. The experimental data of two aluminum alloys shows that, considering frictional effects, the amendment for Oliver-Pharr method is an effective method to improving its test accuracy.