Obtaining high strength and high plasticity in a Mg-3A1-1Zn plate using pre -tension and annealing treatments

In the present study, the usage of recovery structure to obtain a combination of the high strength and high plasticity in a Mg-3A1-1Zn plate was reported. The influence of pre -tension at different temperatures (25 degrees C, 150 degrees C and 200 degrees C) and subsequent annealing (175 degrees C for 6 h) on the microstructure, texture and mechanical properties during re -tension was systematically studied. Our results show that the as used pre -tension plus annealing process can effectively improve the yield strength, especially the one with pre-tension at 150 degrees C and annealing at 175 degrees C for 6 h can increase the yield strength by 61 MPa, meanwhile retain a similar elongation (12.4%) to the initial plate (13.0%). A preferred distribution of prismatic planes with (10-10)//TD exists in both the pre-tensioned samples and the annealed ones. It is found that this preferred distribution hardly varies the SF and the activity of prismatic (a) slip during re tension, and eventually does not contribute to enhancing the yield strength or reducing the plasticity. TEM results show that the annealing of sample pre-tensioned at 150 degrees C develops many dislocation walls together with many areas with a quite low dislocation density. This type of recovery structure mainly accounts for the high strength and high plasticity in the pre -tensioned and annealed samples. (C) 2017 Elsevier B.V. All rights reserved.