Strengthening mechanism and interaction between nano precipitates and defects in wrought Mg-5Li-1Zn-0.5Ag-0.5Zr-xGd alloys.

Mg-5Li-1Zn-0.5Ag-0.5Zr-xGd (x = 2.4, 6) alloys were subjected to multi-directional forging (MDF). The β 1 coherent phase and β incoherent phase precipitated during the MDF process significantly improve the properties of the alloy. The results show that the orientation relationship between the β 1 phase and the matrix is 022 β 1 ∥ 0002 α and 111 β 1 ∥ 1 2 ¯ 10 α.When the dislocations cut through the β 1 phase, the {111} 〈110〉 slip system of the β 1 phases is activated, forming anti-phase boundaries (APBs) by directional motion in the <110> direction, which provides strengthening effects. The APB structure leads to the increase of system energy, deformation resistance, and yield strength. Besides, the activation of the β 1 phases slip system makes the alloys exhibit satisfactory plasticity and toughness. After MDF at 350 °C, Mg-5Li-1Zn-0.5Ag-0.5Zr-2.4Gd alloy has a yield strength of 270 MPa, a tensile strength of 295 MPa, and an elongation of 12.7%, respectively. The results are beneficial for the design and manufacture of high-performance Mg Li alloys. • After multidirectional forging (MDF) at 350 °C, the mechanical properties of the alloys are improved. • When the coherent β1 interacts with defects leads to increasing strength and also promotes satisfactory plasticity. [ABSTRACT FROM AUTHOR]