Microstructure and mechanical properties of Tip/GWZ723 composites adjusted by Tip/Mg laminate structure

Abstract

In this work, the spherical Tip was introduced into Mg-7Gd-2Y–3Zn (GWZ723) alloy, the Tip/Mg laminar-like configuration was constructed by hot extrusion. The layers quantity and interlayer spacing were adjusted by Tip content. The effects of Tip/Mg laminar-like structure parameters on the microstructure, mechanical properties, work hardening and fracture behavior of Tip/GWZ723 composites were investigated. The results indicate that after extrusion, the Tip elongates along the extrusion direction (ED) and form Tip/Mg laminar-like configuration with the matrix. The Tip aspect ratio increases with the Tip content increases, resulting in a pronounced Tip/Mg laminar-like configuration. The addition of Tip promotes DRX, refines the grain size and promotes the precipitation of the lamellar 14H LPSO phase. The Tip/Mg laminar-like configuration induces the accumulation of high-density dislocations at the interface, thereby contributing to hetero-deformation induced (HDI) hardening, which improves the work hardening rate and dynamic recovery rate. With increasing of Tip content, the HDI hardening effect becomes more pronounced. The Tip/Mg laminar-like configuration facilitates strain redistribution, alleviates stress concentration, impacts crack initiation and inhibits crack propagation, enhancing the plasticity of the Tip/GWZ723 composites. At a Tip content of 15 vol%, the 15 vol%Tip/GWZ723 composite exhibits YS of 439 MPa, UTS of 477 MPa and EL of 3.3 %.