Of Ce, Zn, Sc 2195 Aluminum-lithium Alloy Microstructure And Mechanical Properties Of Impact

The effects of different aging treatment (T8, T6) and trace (or small) additions of Ce Zn and Sc on the microstructure and mechanical properties of alloy 2195. By tensile test TEM and SEM observations, the conclusions can be summarized as the followings:1. The addition of Ce can improve significantly texture and mechanical properties of 2195 alloy. The trace addition of Ce can increase the number of the major strengthening phase (T1 and θ' precipitation) and make the major strengthening phase distribute more dispersively and homogeneously. On the other hand, Ce makes the ligement structure of 2195 alloy thinner, Ce improves the fracture behavior of alloy and decrease the tendency of low energy intergranular fracture in a certain degree.2. The small addition of Zn to 2195 alloy leads to an aceeleration of aging response apparently, so the mechanical properties of alloy in T6 temper can get close to that of 2195 alloy in T8 temper. Except for promoting T1 and θ' precipitation smaller and more dispersively, small addition of Zn can form spherular phase containing Zn, So the addition of Zn raises strength of 2195 alloy notably. But small addition of Zn do not change the fracture mechanism of 2195 alloy, and have unfavourable effect on the ductility of 2195 alloy.3. In T8 tempers, the addition of Sc in 2195 alloy can retard the aging, make Tl precipitation in grains distribute more homogeneously and smaller, make Tl precipitation in subgrain boundary and grain boundary smaller and have no PFZ in grain boundary. So the addition of Sc improves ductility and fracture model, but does not decrease the strength of 2195 alloy. Fracture shape of the alloy containing Sc is thin—layer shape + intracrystalline and grain boundary mixture fracture model, not foliated fracture + grain boundary fracture. But the addition of Sc can make the strength of 2195 alloy decrease in T6 temper of higher temperature.