LAUSR

The microstructures and mechanical properties of as‐cast AlLiCuMgZr alloys with high Li content and different Cu/Mg ratios are investigated. The results show that the tensile strength increases and the elongation almost keeps unchanged, with the decrease in Cu/Mg ratio. The tensile fracture exhibits typical intergranular fracture. The main phases of as‐cast alloys are α(Al), δ′(Al3Li), and T2(Al6Li3Cu). With the decrease in Cu/Mg ratio, the size of the δ′(Al3Li) phase increases, and the amount of T2(Al6Li3Cu) phase at the grain boundary decreases. Moreover, the fine S1(Al2MgLi) phase and S′(Al2CuMg) phase are formed inside the grains near the grain boundaries. The improved properties are attributed to the solution strengthening and second‐phase strengthening of δ′(Al3Li).