Effect Of Heat Treatment On Microstructure And Properties Of ADC12 Al Alloy

ADC12 alloy belongs to Al-Si-Cu aluminum casting alloys which can be strengthened by heat treatment. ADC12 has good casting character, high strength, low expansion coefficient, good corrosion-resistant performance and good machinability. Good combination property can be gained by controlling the addition of Cu, Mg and Mn in ADC12 alloy. The solution and precipitation strengthening process plays a key role in strength of ADC12 alloy which is often used at artificial aging. To attain good strengthening effect with good thermal intensity and wear-resisting property, it is very important to determine optimized heat treatment process parameters. The purposes of this paper were a search for optimizing heat treatment process parameters for ADC12 alloy. The influence of heat treatment for microstructure of ADC12 alloy was studied also.In this paper, by the method of microstructure observation (optical microscope, SEM and TEM) combined with mechanical property test and differential thermal analysis, ADC12 alloy was studied for heat treatment strengthening and determining optimized heat treatment parameters. Some main research results are presented as the following:(1) ADC12 alloy was treated by solution heat treatment and artificial aging according to orthogonal experimental design programme, and the mechanical property of alloy was measured to determine optimized heat treatment process parameters. The optimized heat treatment process parameters were determined by orthogonal experimental design and range analysis as followings: solution treatment temperature was 520℃, solution treatment time was 5h, artificial aging temperature was 170℃, artificial aging time was 10h. The property of alloy under this condition was determined as followings: tensile strength was 283MPa at room-temperature, extensibility was 2.52% at room-temperature; tensile strength was 163MPa at high temperature, extensibility was 4.66% at high temperature; hardness was 125.4HB; wear extent was 0.0016g.(2) Influence of heat treatment for alloy microstructure was studied in this paper. By...