摘要
将粉末冶金与等通道转角挤压相结合,采用真空热压烧结的方法固结纯铝粉末后,在不同挤压温度与挤压道次下对烧结体进行等通道转角挤压实验,测试材料的致密度、微观组织和力学性能,分析晶粒细化与致密机理。结果表明:常温下1道次等通道转角挤压后晶粒细化至9.62μm左右,硬度由10.35 HV提升至49.73 HV,相对密度由初始的0.8796提升至0.9104。150℃下4道次挤压后试样相对密度提升至0.9752,硬度提升至47.20 HV。通过光学显微镜和扫描电镜观察试样组织形貌,结合硬度数据分析,得到当致密程度相近时,细晶强化对纯铝粉末烧结体等通道转角挤压后的力学性能起决定作用。电化学实验结果表明:纯铝粉末烧结体耐蚀性较差,但经等通道转角挤压后耐蚀性大幅提升,优于高纯铝铸锭,且随挤压道次的增加,试样耐蚀性提升。
Powder metallurgy was combined with equal channel angular extrusion.After consolidating pure aluminum powder by vacuum hot press sintering,the sintered body was subjected to equal channel angular extrusion experiments at different extrusion temperatures and extrusion passes.The density,microstructure and mechanical properties of materials were tested,and grain refinement and compaction mechanism were analyzed.The results show that the grain size is refined to about 9.62μm after one-pass equal channel angular extrusion at room temperature,the hardness increases from 10.35 HV to 49.73 HV,and the relative density increases from the initial 0.8796 to 0.9104.The relative density of sample is increased to 0.9752 after four-passes extrusion at 150℃,and the hardness is increased to 47.20 HV.The morphology of sample was observed by optical microscope and scanning electron microscope,combined with the analysis of hardness data,when the compactness degree is similar,the fine-grain strengthening plays a decisive role in the mechanical properties of the pure aluminum powder sintered by equal channel angular extrusion.Electrochemical experiment results show that the corrosion resistance of pure aluminum powder sintered body is poor,but the corrosion resistance is greatly improved after equal channel angular extrusion,which is better than that of high-purity aluminum ingot,and with the increase of extrusion passes,the corrosion resistance of sample increases.
作者
刘芳
陆郡
崔力立
LIU Fang;LU Jun;CUI Li-li(School of Materials Science and Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)
出处
《塑性工程学报》
CAS
CSCD
北大核心
2021年第11期78-86,共9页
Journal of Plasticity Engineering
关键词
真空热压烧结
等通道转角挤压
微观组织
力学性能
耐蚀性
vacuum hot pressing sintering
equal channel angular extrusion
microstructure
mechanical properties
corrosion resistance
