摘要
利用不同前角刀具对纯铜材料进行了大应变挤出切削加工,并将制备的超细晶纯铜切屑在不同温度下进行退火处理。通过金相显微观察、扫描电镜观察和维氏硬度检测等手段,分析了材料在变形前后及热处理前后的微观结构和性能变化。结果表明：30°前角刀具加工时,纯铜材料晶粒已明显细化,由大约100μm粗晶细化至亚微米级拉长晶,并且宏观硬度从基体的85 HV0.05提升至135 HV0.05;而10°刀具加工时,晶粒进一步细化为等轴细晶,甚至出现部分纳米晶,硬度也进一步提升至150 HV0.05。同时,前角越小,开始再结晶温度越低,再结晶完成时晶粒越小,硬度值越高;此外,无论10°还是30°刀具加工,超细晶纯铜材料均可在240℃下保持良好的热稳定性。
The annealing treatments were conducted under different temperatures for ultrafine-grained pure copper produced by large strain extrusion machining with different tool rake angels. The microstructure and properties evolution before and after deformation and annealing were studied by means of optical microscope,scanning electron microscope and micro-hardness test,etc. The results show that when processed with30° rake angle tool,the grains of pure copper material are obviously refined from about 100 μm to sub micron elongated ones,and the macrohardness is increased from 85 HV0. 05 to 135 HV0. 05. However,when processed with 10° rake angle tool,the grains are further refined to fine equiaxed grains,even to nanocrystals,the microhardness is further enhanced to 150 HV0. 05 as well. Additionally,smaller the rake angle,lower temperature the recrystallization begins and smaller the grain after recrystallization,higher the micro-hardness as well. Whatever rake angle tool is used,10° or 30°,the ultrafine-grained pure copper can maintain a good thermal stability at temperatures below 240 ℃.
出处
《金属热处理》
CAS
CSCD
北大核心
2018年第1期121-125,共5页
Heat Treatment of Metals
基金
国家自然科学基金(51375174)
关键词
超细晶纯铜
大应变挤出切削
刀具前角
组织
硬度
热稳定性
uhra fine-grained pure copper
large strain extrusion machining
tool rake angle
microstrueture
hardness
thermal stability
