Effects of Heat Treatment on Microstructure,Thermal Conductivity,and Mechanical Properties of Composite Modified AlSi10MnMg Alloy
AlSi10MnMg alloy specimens were fabricated by Sr and Ce composite modification combined with squeeze casting,and effects of heat treatment on microstructure and properties of alloy were investigated.The results indicate that the structure become more uniform after heat treatment,where the eutectic Si phase is transformed from worm-like and coral-like to finer particles,and boundary morphology is more spheroidized,with increasing electron transfer efficiency and thermal conductivity.After 540℃×0.5 h solid solution treatment,the thermal conductivity attains a maximum of 194.53 W/(m·K),which is increased by 7.07%compared to that of one with Sr+Ce composite modifi-cation.After T6 heat treatment,the thermal conductivity of the alloy tends to decrease due to the partially eutectic Si precipitation and lattice distortion.The overall tensile strength of the alloy is declined with increase in solid solution time,while elongation is increased,and the tensile and yield strength are further enhanced after T6 heat treatment,whereas elongation is decreased considerably due to the precipitation of alloy elements.After 530℃×0.5 h solid solu-tion+180℃×6 h T6 aging heat treatment,the tensile strength,yield strength and elongation reach 348.26 MPa,263 MPa and 14.92%,which is enhanced by 52.1%,205.8%and 2.1%compared to those of ones with Sr+Ce com-posite modification,respectively.
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