Effects of process parameters on mechanical properties andmicrostructures of creep aged 2124 aluminum alloy
(1. State Key Laboratory of High-performance Complex Manufacturing,
Central South University, Changsha 410083, China;
2. School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China)
Central South University, Changsha 410083, China;
2. School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China)
Abstract: A series of tests were carried out to investigate the effects of process parameters on mechanical properties and microstructures of 2124 aluminum alloy in creep aging process. The results show that creep strain and creep rate increase with the increase of aging time, temperature and applied stress. The hardness of specimen varies with aging time and stress in a low-to-peak-to-low manner. No significant effect of temperature on hardness of material is seen in the range of 185-195 °C. The optimum mechanical properties are obtained at the conditions of (200 MPa, 185 °C, 8 h) as the result of the coexistence of strengthening S" and S′ phases in the matrix by transmission electron microscopy (TEM). TEM observation shows that applied stress promotes the formation and growth of precipitates and no obvious stress orientation effect is observed in the matrix.
Key words: aluminum alloy; creep aging behavior; age hardening; mechanical property; microstructure; process parameter