The effects of heat treatment and strontium （SO addition on the microstructure and mechanical properties of ADC12 alloys were investigated, and two-stage solution treatment was introduced. The results indicated that ...The effects of heat treatment and strontium （SO addition on the microstructure and mechanical properties of ADC12 alloys were investigated, and two-stage solution treatment was introduced. The results indicated that the addition of Sr obviously refined the microstructure of ADC12 alloys. When 0.05 wt% Sr was added into the alloy, the eutectic Si phase was fully modified into fine fibrous structure; a-A1 and fl-A15FeSi phases were best refined; and the eutectic AlzCu phase was modified into block-like AlzCu phase that continuously distributed at the grain boundary. The ultimate tensile strength （UTS） （270.63 MPa） and elongation （3.19%） were increased by 51.2% and 73.4% respectively compared with unmodified alloys. After the two-stage solution treatment （500 ~C, 6 h＋520 ~C, 4 h）, for 0.05 wt% Sr modified ADC12 alloys, the Si phases transformed into fine particle structure and AlzCu phases were fully dissolved. The peak hardness value of the alloys processed by the two-stage solution treatment was increased by 8.3% and 6.8% respectively compared to solution treatment at 500 ~C and 520 ~C. After the aging treatment （175 ~C, 7 h）, the hardness and UTS were increased by 38.73% and 13.96% respectively when compared with the unmodified alloy.展开更多
基金Project（51364035） supported by the National Natural Science Foundation of China Project（20133601110001） supported by the Ministry of Education Tied up with the Special Research Fund for the Doctoral Program for Higher School, China+1 种基金 Project（KJLD14003） supported by the Loading Program of Science and Technology of College of Jiangxi Province, China Project（2012-CYH-DW-XCL-002） supported by the Production and Teaching and Research Cooperation Plan of Naaachaaag Non-party Experts and Doctor, China
文摘The effects of heat treatment and strontium （SO addition on the microstructure and mechanical properties of ADC12 alloys were investigated, and two-stage solution treatment was introduced. The results indicated that the addition of Sr obviously refined the microstructure of ADC12 alloys. When 0.05 wt% Sr was added into the alloy, the eutectic Si phase was fully modified into fine fibrous structure; a-A1 and fl-A15FeSi phases were best refined; and the eutectic AlzCu phase was modified into block-like AlzCu phase that continuously distributed at the grain boundary. The ultimate tensile strength （UTS） （270.63 MPa） and elongation （3.19%） were increased by 51.2% and 73.4% respectively compared with unmodified alloys. After the two-stage solution treatment （500 ~C, 6 h＋520 ~C, 4 h）, for 0.05 wt% Sr modified ADC12 alloys, the Si phases transformed into fine particle structure and AlzCu phases were fully dissolved. The peak hardness value of the alloys processed by the two-stage solution treatment was increased by 8.3% and 6.8% respectively compared to solution treatment at 500 ~C and 520 ~C. After the aging treatment （175 ~C, 7 h）, the hardness and UTS were increased by 38.73% and 13.96% respectively when compared with the unmodified alloy.
