Microstructures and mechanical properties of2014aluminium alloy
forgings made by a new process①
forgings made by a new process①
(1. Department of Materials Science and Engineering,
Central South University of Technology, Changsha 410083, P.R.China;
2. Southwestern Aluminium Fabrication Plant, Chongqing631326, P.R.China)
Central South University of Technology, Changsha 410083, P.R.China;
2. Southwestern Aluminium Fabrication Plant, Chongqing631326, P.R.China)
Abstract: The triangular 2014 aluminium alloy forgings were made by a new process and the traditional process. The results showed that the mechanical properties of the forgings made by the new process are far higher than that in the standard of GB223-84, and also higher than that in the standard of EL/53MI-94; moreover, the mechanical properties are almost the same in each direction, and anisotropies are very small. The grains and 2nd phases were analyzed by using TEM and SEM, the results indicate that very fine grains (3~6μm)appear in an approximately isometric way, and a large number of 2nd submicrophases(0.05~0.15μm) disappear in no apparently preferred orientation distribution because the new process involves multidirectional heavy plastic deformation (λ=12), solution(500℃/400 min) and ageing(165℃/10 h) heat treatments for a long time at high temperatures. These refined grains, 2nd submicrophases and their almost homogeneous distribution can make it possible for the forgings to display high mechanical properties.
Key words: 2014 aluminium alloy forging; mechanical properties; microstructures