Influence of Modification on Microstructure and Mechanical Properties of Hypereutectic Al-Si Alloy

The A390 hypereutectic Al-Si alloy with 18wt% Si content was prepared through the melt modified by binary and ternary modifiers during the casting process.The influence of modification on microstructure and mechanical properties of A390 hypereutectic Al-Si alloy was investigated by optical microscopy analysis,scanning electron microscopy observation,wear resistance test and tensile strength test.The results show that after the modification of A390 alloy,the corner angle of the primary Si was inactivated,and its size was below 30 μm.Eutectic Si was spheroidized,and the grain was refined.Mechanical properties of the modified alloy were improved apparently.After ternary modification,compared to non-modification,the elongation and tensile strength of A390 alloy at room temperature had been increased by 150% and 31%,respectively.Wear resistance of the A390 alloy was also improved.The wear resistance in ternary modification was mainly microscopic cutting.