可压缩纯钼粉末烧结材料的塑性变形行为及影响因素  

Plastic deformation behavior and influencing factors of pure Mo powder sintered material

作　　者：李永志[1,2] 薛克敏[1] 李萍[1] 汪洋[1] 白小波[2] 

机构地区：[1]合肥工业大学材料科学与工程学院,合肥230009 [2]九江学院机械与材料工程学院,九江332005

出　　处：《粉末冶金材料科学与工程》2011年第6期849-855,共7页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金资助项目(50875072);霍英东教育基金会资助项目(121053);安徽省优秀青年科技基金项目(10040606Y21)

摘　　要：基于单轴压缩实验,研究纯钼粉末烧结材料的塑性变形行为及其影响因素。结果表明:可压缩纯钼粉末烧结材料的塑性变形行为对初始相对密度、温度和应变速率的变化相当敏感,其流动应力随应变速率的增加而增加,随温度的升高而减小;高温条件下材料对应变速率不太敏感,但初始相对密度在低温状况下对流动应力的影响更甚;对压缩后试样的微观组织分析显示:初始平均粒径为44.0μm的粗大等轴晶组织经过约35%的单轴压缩后,其中心主变形区域得到平均粒径为1.45μm完全致密的超细晶组织;初始相对密度越大,材料屈服强度越低,出现破裂的时间越早;其硬度增加速率对温度变化不敏感,而提高温度则有利于降低屈服强度。The plastic deformation behavior and the influencing factors of pure Mo powder sintered materials were studied based on uniaxial compression experiments. The results show that the flow stress of pure Mo powder sintered material is very sensitive to the changes of initial relative density, temperature and strain rate. The flow stress increases with increasing strain rate and decreases with increasing temperature, and the materials under high temperature conditions is not very sensitive to strain rate, but initial relative density under low temperatures conditions has a greater effect on the flow stress. Macrostructure analysis after compression show that the initial coarse equiax-grained microstructure with mean grain size of 44.0 ~tm becomes fully dense ultra-fine grained microstructure with mean grain size about 1.45 ~tm after 35% reduction in the main deformation zone and it has the growth of structure as branches and leaves; Under higher initial relative density, the material has lower yield strength and the earlier the rupture occurred; increasing rate of hardness is not sensitive to the change of temperature, while the increase in temperature is beneficial to the reduction of yield strength.

关 键 词：纯钼粉 烧结材料 变形行为 组织 影响因素 

分 类 号：TG316.2[金属学及工艺—金属压力加工] TF124[冶金工程—粉末冶金]