茅梦云,彭林法,来新民

上海交通大学 机械系统与振动国家重点实验室； 上海市复杂薄板结构数字化制造重点实验室, 上海 200240

出版日期:2019-03-28发布日期:2019-03-28
通讯作者:来新民，男，教授，博士生导师，电话(Tel.):021-34206303; E-mail: xmlai@sjtu.edu.cn.
作者简介:茅梦云(1989-)，男，江苏省丹阳市人，博士生，主要研究方向为金属微成形.
基金资助:国家重点研发计划（2017YFB0103001）资助项目

Experimental Study of the Grain Size Effect on Scratching Behaviors of Pure Copper

MAO Mengyun,PENG Linfa,LAI Xinmin

State Key Laboratory of Mechanical System and Vibration; Shanghai Key Laboratory of Digital Manufacture for Thin-Walled Structures, Shanghai Jiao Tong University, Shanghai 200240, China

Online:2019-03-28Published:2019-03-28

摘要/Abstract

摘要： 金属薄板成形过程中由于模具与材料表面粗糙度相近，摩擦中的犁沟效应会对材料表面的变形行为产生重要影响，进而影响薄板材料的成形性能.为此，通过圆锥划伤实验，研究不同圆锥角度下不同晶粒尺寸材料的变形及损伤行为.结果表明：随着圆锥角度的增大，材料内裂纹产生的位置从划痕顶部逐渐转变为划痕中上部，材料的流动方向则从沿圆锥表面向上逐渐转变为向圆锥两侧扩展；晶粒尺寸的增大能够抑制划伤过程中材料内部裂纹的产生，从而减少划痕内的裂纹区域；材料的划伤硬度和划痕前端的材料堆积高度随着晶粒尺寸的增大而减小；材料划伤行为的晶粒尺度效应主要来自于晶粒尺寸对材料流动及断裂性能的影响.研究结果能够加深对金属成形过程中摩擦行为的认识，并对金属成形工艺的参数设计提供理论指导.
关键词: 犁沟效应, 表面划痕, 晶粒尺寸, 金属成形
Abstract: During the sheet metal forming process, the ploughing effect had an important influence on the magnitude of surface deformation due to the similar roughness of tool-workpiece. To have an in-depth understanding of the ploughing process, single cone scratching tests of different grain sized materials were conducted in this study. It was found that the location of cracks and the flow directions of materials in scratching process varied significantly with the change of cone angle. The increase of grain size can restrain the initiation of cracks and lower the entire strain caused by the moving of the rigid cone, which in a row decrease the scratching hardness and pileup height in scratching process. The results of this study can improve the understanding of the ploughing process and further help the optimization of the surface quality of the metal-deformed products.
Key words: ploughing effect, surface scratching, grain size, metal forming


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