| Abstrakt: |
The competitive precipitation behavior between T1 and σ phases in Al-Cu-Li alloy was studied by hardness test, XRD and TEM observation. The hardness test results show that the changing curves are related to the densities of vacancies and dislocations, and competitive precipitation between age hardening precipitates. T1 phases give rise to the rapid age hardening. XRD results indicates that there exists an alternation increase in peak value of diffraction intensity ranged from 40 to 45° of the aged alloy for various ageing time. About four precipitation sequences occur during ageing of Al-Cu-Li alloy, including δ', θ, T1 and σ sequences. Competitive kinetics between T1 and σ phases result in the phenomenon of different precipitation behavior. |
