Preparing Al-20%Sn Alloy by Mechanical Alloying Combining Cold Compacting and Sintering

First Al-20%Sn alloy powders were prepared by mechanical alloying method,and then the bulk alloy was prepared by different compacting and sintering processes.The effects of milling and sintering processes on the microstructure of Al-20%Sn alloy were characterized by X-ray diffraction and scanning electron microscopy.The results show that microstructure of fine Sn phase distributing homogeneously in Al matrix could be gained by choosing high milling speed (250 r·min-1),large ball-to-powder mass ratio (30∶1) and suitable milling time (40 h).When the sintering temperature is below eutectic temperature,the Sn phase distributed homogeneously in Al matrix.However,when the sintering temperature exceeded the eutectic temperature,coarsening of the Sn phase occured obviously and there was apparent netlike distribution of Sn phase.The grain growth of Al-20%Sn alloy could be restrained effectively by using high compacting pressure and sintering pressure in sintering process,and the homogeneous distribution of fine Sn phase in Al matrix was still kept.