一种用微弯曲实验测定内禀材料长度的新方法  

A modified method of micro-bend test for measuring the intrinsic material length

作　　者：俞叶峰[1] 穆宏巍[1] 邹化民[1] 

机构地区：[1]武汉大学物理科学与技术学院,武汉430072

出　　处：《材料研究学报》2007年第1期37-40,共4页Chinese Journal of Materials Research

基　　金：国家自然科学基金50471028资助项目.

摘　　要：提出了一种用微弯曲实验测定材料的与应变梯度塑性相联系的内禀长度的新方法．由一组不同的加载时曲率半径R_i和对应的卸载后曲率半径R_i^F的比值与R_i的关系,求出屈服强度与杨氏模量的比和硬化系数与杨氏模量的比;再应用这两个比值求出不同样品厚度的无量纲弯曲力矩与表面应变的实验关系曲线,对曲线拟合求出材料的内禀长度．将这种方法用于测定铝的内禀材料长度,研究其弯曲强度的尺寸效应,所得结果与前人用微弯曲和微拉伸两种实验方法得到的结果符合得很好．A modified micro-bend test method for determining the intrinsic materials length in strain gradient plasticity has been developed and described. The ratios of yield strength over Young＇s modulus and of hardening coefficient over Young＇s modulus are determined by fitting the variation of the ratio of the curvature radius in loading state, Ri, over the curvature radius in unloading state, Ri^F, with the loaded radius of curvature, Ri. By using these two ratios, the experimental curves of the non-dimensional moment and the surface strain in loading state for different thicknesses are obtained, by which the intrinsic material length can be determined. This method was employed to study the size effect in bending strength of aluminum. The results agreed very well with those measured with both micro-bending and micro-tensile tests reported before.

关 键 词：材料检测与分析技术 微弯曲实验 材料内禀长度 应变梯度塑性 

分 类 号：TG115[金属学及工艺—物理冶金]