Mechanical Alloying Preparation and Properties of 57.6Ag-22.4Cu-10.5In-9.5Sn Alloy Powders

57.6Ag-22.4Cu-10.5In-9.5Sn alloy powders were prepared for the middle temperature alloy solder with of melting point 400-600 ℃ by mechanical alloying method.The effects of different milling times on alloying process,phase compositions,melting properties and micro-appearance of the powders were studied by XRD,DSC,SEM and EDS.The results indicate that 57.6Ag-22.4Cu-10.5In-9.5Sn alloy powders can be obtained by mechanical alloying method when milling time above 30h.As milling time was prolonged,the particte size of alloy powders became smaller constantly,and their shape changed from sheet to spherical,gradually.The alloy powders showed the best sphericity and had a size distribution from 5 to 35 μm when milling time is 60 h.The lowest melting point was determined to be 494.3 ℃.