| Title |
Effect of Solution Treatment Temperature and tensile Test Temperature on the Superplasticity of 7475 Al - Alloy |
| Authors |
강길순(Gil Soon Kang) ; 박종우(Jong Woo Park) ; 문인기(In Ge Moon) ; 신동혁(Dong Hyuk Shin) ; 맹선재(Sun Jae Maeng) |
| Abstract |
Effect of solution treatment temperature as well as tensile test temperature on the microstructure and superplasticity of high strength 7475 Al alloy was studied in order to optimize the grain refining process and superplastic forming conditions. Maximum grain refining was achieved by an application of high temperature solution treatment at 520℃ (higher than usual practice of 480℃) and also the maximum superplastic elongation was obtained at the grain size minimum. Maximum grain refining by a high temperature solution treatment is attributed to the dissolution of more solute atoms which are reprecipitated to optimal distribution for recrystallization at overaging stage. High temperature tensile test at 535℃ brought better results(elongation of about 1500% at an initial strain rate of 2.1×10^(-3)/s) than that of 516℃(usual practice). Effective accomodation for grain boundary sliding, assisted by high temperature diffusion, is considered responsible for the results. |