Evaluation of Steel Fracture Toughness Based on Strain Energy Density of Berkovich Indentation
宗源 1王谦之1
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作者信息
1. 南京航空航天大学机电学院,南京 210016
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摘要
为改善压痕法测试断裂韧性过程中测量标准不同和精度不足的问题,基于临界压痕能量(Critical indentation energy,CIE)法,提出了基于Berkovich压痕应变能量密度(Strain energy density,SED)评估钢材断裂韧性的方法.同时考虑弹性和塑性能量并修正临界总压深,评价了9种钢材的韧性.结果表明,发现仅考虑塑性能量所测量韧性的相对误差在5%～20%,而本文同时考虑弹性和塑性能量所测量韧性的相对误差在5%以内.同时,确定临界总压深的拟合范围需要避开材料近表面弹性模量上升的区域,改善了基于CIE法使用Berkovich压头评估钢材断裂韧性的精确度.
Abstract
In order to improve the problem of insufficient measurement scale and accuracy in the process of fracture toughness testing by indentation method,a method for assessing the fracture toughness of steel based on Berkovich indentation strain energy density(SED)is proposed based on the critical indentation energy(CIE)method.The fracture toughness of nine steels is evaluated by considering both elastic and plastic energies and correcting the critical total pressure depth.The results show that the relative error of the toughness measured by considering only the plastic energy is found to be in the range of 5%to 20%,whereas the relative error of the toughness measured by considering both the elastic and plastic energies is found to be within 5%.At the same time,determining the fitting range for the critical total indentation depth requires avoiding the region where the elastic modulus of the material rises near the surface.These improve the accuracy of evaluating the fracture toughness of steel based on the CIE method using the Berkovich indenter.
关键词
断裂韧性/应变能量密度/压痕/钢材表面/测试
Key words
fracture toughness/strain energy density/indentation/steel surface/test
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