高能球磨稀土高硅铝合金粉末性能表征

对快速凝固法制备得到的Al-20Si-0.35RE合金进行不同时间的高能球磨, 然后对球磨后的粉末进行多次热压变形, 采用XRD, ESEM以及TEM等表征变形前后合金粉末的显微组织, 并对变形后合金的导电性能进行了研究. 研究发现快速凝固Al-20Si-0.35RE合金粉末的显微组织主要由细小的Al-Si固溶体(0.3～0.5 μm)、初晶硅、稀土铝硅化合物(0.16～0.3 μm)组成; 随着球磨时间延长, 颗粒粒径显著减小; 经过多次热压变形后合金晶粒显著细化, 晶格畸变减小, 位错钉扎稀土化合物, 形成类似表面渗流效应, 合金导电率提高至70%IACS.

Characterization of Rapidly Solidified Al-20Si-0.35RE Powder by High Energy Ball Milling

The Al-20Si-0.35RE alloy which was prepared by rapid solidification was processed by hot pressing after ball-milled for different time. X-ray diffraction spectrum (XRD), environmental scanning electron microscope (ESEM) and transmission electron microscope (TEM) were used to investigate the microstructure of alloy powder before and after hot pressing. Its conductivity was also studied. The microstructure of as-atomized alloy powder was consisted of fine Al-Si solid solution (0.3～0.5 μm), primary silicon phase and rare earth Al-Si compound (0.16～0.3 μm). With the increase of high energy ball milling time, the size of particles was reduced significantly. After several hot pressing processes, the grains were refined obviously and the distortion of lattice decreased significantly. The conductivity of Al-20Si-0.35RE could be improved to 70%IACS for surface seepage effect induced by the dislocation pinning of rare earth compounds.