Al-Pb粉末在机械合金化过程中的粒度及形貌演变

Morphology and Size Development of Al-Pb Powders during Mechanical Alloying

采用XRD ,SEM ,TEM和粒度分析仪对Al 15 %Pb和Al 15 %Pb 4%Si 1%Sn 1.5 %Cu(质量分数 ,% )混合粉末在机械合金化过程中的粒度及形貌演变进行了研究。结果表明 :混合粉末经球磨后都可以获得纳米晶 ,球磨对Pb的细化明显大于对Al的细化作用 ;在相同的球磨时间下 ,添加有Si,Sn ,Cu混合粉末的Al,Pb晶粒更小 ,其获得纳米晶的时间更短。由于冷焊与断裂在MA不同阶段的主导不同 ,Al 15 %Pb 4%Si 1%Sn 1.5 %Cu粒子经历了快速长大、快速减小和慢速减小 3个阶段 ;而Al 15 %Pb粒子细化则是增大—减小的反复过程 ,在球磨过程中Si作为硬度高的脆性粒子难于完全实现合金化 ,而Sn ,Cu合金化速度较快。

Morphology and size development were investigated on the Al-15%Pb and Al-15%Pb-4%Si-1%Sn-1.5%Cu (mass fraction %) high energy ball milled powders using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and particle size analyzer. The experimental results show that the nanocrystalline powders are synthesized and the effect of ball milling is more evident to lead than to aluminum at refining particle. At the same ball milling time, the Al and Pb crystalline of Al-15%Pb-4%Si-1%Sn-1.5%Cu are less than those of Al-15%Pb. It requires short milling time of the nanocrystalline powders synthesized by getting into Si, Sn, Cu in system. Due to cooled welding and fracture play different dominating role during mechanical alloying respectively, the particles of Al-15%Pb-4%Si-1%Sn-1.5%Cu mixture powders under go three stages: increase in size with high speed, decrease in size with high speed and decrease in size with low speed, but the particles of Al-15%Pb mixture powders are repeat increasing and decreasing. Otherwise, brittle element powder of silicon is more difficulty alloying, but Sn and Cu are more easily alloying in the MA process.