摘要
Al-Cu-Li alloy is a huge potential alloy for aerospace industry due to its low density and excellent comprehensive performances.In this study,the microstructures and mechanical properties of a novel cast Al-Cu-Li alloy during the heat treatment were investigated.Results showed that most of the secondary phases along grain boundaries in as-cast state were dissolved into the Al matrix after homogenization and solution treatment,while the Cu-rich phases were slightly segregated once again on grain boundaries after aging.A relatively good combination of strength and ductility(average ultimate tensile strength of 430 MPa and elongation of 8.9%)was obtained after natural aging.Transmission electron microscopy(TEM)results revealed that there was a complicated precipitate distribution in this cast alloy after natural aging.Compared with the similar alloys which introduced dislocations before aging,the density of T1(Al_(2)CuLi)phases was decreased but the size was increased.The low volume fraction of d0 phase,medium density of needle-shaped precipitates and relativity narrow precipitates-free zone with varying widths near grain boundary are the reasons accounting for the improvement of performances.
基金
the Key Research and Development Project of Shandong Province(No.2018CXGC0403)。
