Enhanced ductility by tailoring precipitations in micron TiB2 reinforced Mg-Li matrix composites with high modulus

Abstract

The development and application of lightweight materials boasting an elevated elastic modulus have emerged as a focal point in the realm of materials research. A novel Mg-8Li-3Al-2Zn-0.5Y (wt.%, LAZ832) matrix composite reinforced with ex situ micron-sized TiB2 particles was introduced in this work. The uniformly distributed TiB2 particles were achieved through ball milling pretreatment and subsequent hot extrusion. A comprehensive analysis of the composite's microstructure and mechanical properties was conducted. Mg-Li-Al-Zn precipitation regions formed at the TiB2 interface was identified firstly. This softening region significantly enhanced the ductility of the composite by reducing the dislocation density and stress concentration around the TiB2 particles. The ductility and the elastic modulus of the as-extruded composite increased significantly with ideal ultimate tensile strength (UTS = 270 MPa). This work highlights an ultra-light Mg-Li matrix composite attaining high modulus (60 GPa) and notable elongation to fracture (19.1 %), demonstrating significant potential for future applications.

Keywords

• Mg-Li composite
• Elastic modulus
• Precipitations
• Mechanical properties