基于纳米压入技术表征金属材料塑性参数

Characterization of the Plastic Properties of Metals by Spherical Indentation-Based Method

基于球形压入的工作方式,重点研究金属材料塑性参数的表征方法。首先,选取压入总功和Meyer系数作为主要分析参数。其次,利用孔洞模型、相似解和数值模拟等工具,分别建立压入总功和Meyer系数与材料塑性参数之间的半解析关系式。由此,提出一种金属材料塑性参数表征方法,该方法可以避免对接触半径的测量,并能通过一次加载试验同时识别屈服强度和硬化指数,确保了方法的可操作性和便捷性。最后,选用4种常用金属材料进行压入和拉伸试验,通过将该方法的预测结果与拉伸试验结果比对可知,该方法能较准确地识别材料的塑性力学参数。

Characterization method for the plastic properties of metals was investigated based on spherical indentation. First the indentation work and Meyer index were used as main analysis parameters. Then the relationships between indentation work and Meyer index and plastic properties were established by means of expanding cavity models, finite element computations and dimensional analysis. Therefore, a new method for plastic property characterization was put forward. It can avoid measuring the contact radius, and yield strength and hardening exponent can be determined by single loading test, which ensures its convenience. Finally four kinds of metals were selected for indentation and tensile test. By comparing the predicted results and tested result, we know that the proposed method can determine the plastic properties of materials accurately.