摘要
目的提高硬质合金表面残余压应力和显微硬度,为后续研究激光冲击对硬质合金刀具耐磨损性能的影响提供指导依据。方法采用脉冲波长为1064 nm、脉冲宽度为15 ns的Nd:YAG激光器,对WC-Co硬质合金表面进行冲击强化处理。通过数字显微硬度计、X-350型残余应力测试仪,分别评价激光冲击前后硬质合金硬度和残余应力的分布,并通过扫描电镜对其表面形貌、截面微观组织进行分析。结果激光能量为5 J时,表面存在大量孔洞,WC晶粒未发生变化。激光能量高于10 J时,孔洞和凹陷区基本消失且表面WC晶粒细化。经激光冲击后,表面形成10~23?m的致密层,在塑性变形区γ相均匀分布。与未冲击表面相比,冲击后的显微硬度和残余压应力分别提高34.2%、77%,且平均摩擦系数由0.5033降低到0.4214。结论激光冲击改善了WC-Co硬质合金微观组织结构和残余应力状态,提高了硬度,有利于提高WC-Co硬质合金的耐磨性。
The work aims to improve residual compressive stress and microhardness on cemented carbide to provide guid- ance for the study on wear resistance of cemented carbide tools in subsequent laser shot peening. Nd：YAG laser with 1064 nm long pulse wave and 15 ns wide pulse was used to impact and strengthen the surface of WC-Co cemented carbide. Digital mi- crohardness tester and X-350 residual stress tester were respectively adopted to evaluate the distribution of hardness and residual stress on cemented carbide before and after LSP （Laser Shot Peening）. The scanning electron microscope was used to analyze surface morphology and the section microstructure. At the laser energy of 5 J, the surface had lots of holes but WC grains did not change obviously. At the laser energy above 10 J, holes and depressions basically disappeared and WC grains were refined.Alter LSP, 10-23 μm dense layer was formed on surface and uniformly distributed on y phase in plastic deformation area. Compared with the su,face without LSP, the microhardness and the residual compressive stress increased by 34.2% and 77% respectively and the average fiiction coefficient decreased from 0.5033 to 0.4214 after LSP. LSP improves microstructure, residual stress state and micro- hardness of WC-Co cemented carbide and is beneficial to improve the wear resistance of WC-Co cemented carbide.
作者
张超
花银群
帅文文
李志宝
ZHANG Chao;HUA Yin-qun;SHUAI Wen-wen;LI Zhi-bao(Jiangsu University, Zhenjiang 212013, China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2018年第4期230-235,共6页
Surface Technology
基金
国家自然科学基金资助项目(51641102)~~
作者简介
张超（1991-），男，硕士研究生，主要研究方向为金属材料表面改性。;通讯作者：花银群（1963-），男，博士，教授，主要研究方向为金属材料表面改性。
