摘要
The aging precipitation structure and the properties of Al-Li-Cu-Zr alloys with 3 different Cu/Li ratios have been studied.Experimental results show that the aging hardening of the alloys consists of two steps:The first is strengthened by δ′-phase(δ′+T_1 phase in alloy No.3),and the second by δ′+T_1 phase(δ′+T_1+θ′phase in alloy No.3).The plate of T_1-phase can absorb the Li atoms from δ′ particles when the plate bumped into δ′-phase,and therefore, these δ′ phase particles become smaller and gradually disappear.The strength and hardness increase with the increase of Cu/Li ratio and cuases a decrease in plasticity.The crack mode would change from transgranular to intergranular.This is due to the precipitation of the equi- librium phases contained Cu at grain boundaries.
The aging precipitation structure and the properties of Al-Li-Cu-Zr alloys with 3 different Cu/Li ratios have been studied.Experimental results show that the aging hardening of the alloys consists of two steps:The first is strengthened by δ′-phase(δ′+T_1 phase in alloy No.3),and the second by δ′+T_1 phase(δ′+T_1+θ′phase in alloy No.3).The plate of T_1-phase can absorb the Li atoms from δ′ particles when the plate bumped into δ′-phase,and therefore, these δ′ phase particles become smaller and gradually disappear.The strength and hardness increase with the increase of Cu/Li ratio and cuases a decrease in plasticity.The crack mode would change from transgranular to intergranular.This is due to the precipitation of the equi- librium phases contained Cu at grain boundaries.
