Effect of Ti particles on the microstructure and mechanical properties of as-extruded Titanium-reinforced Mg-9Gd-4Y–1Zn–1Mn matrix composites

Abstract

In this work, TiP/VW94 composites were prepared by semi-solid stirring assisted ultrasonic vibration followed by hot extrusion. The results indicate that the presence of Ti particles can promote the precipitation of lamellar long period stacking ordered structure (LPSO) while inhibiting the precipitation of block-shaped LPSO during heat treatment due to the dislocations introduced by Ti particles. Besides, the content and size of RE-rich phase decrease with the increase of the Ti particle content. The lamellar LPSO can hinder recrystallization and RE-rich phase can hinder grain growth. The addition of Ti particles decreased the grain size, recrystallization fraction and texture intensity of as-extruded TiP/VW94 composites compared with VW94 matrix alloy. The 5%TiP/VW94 composite presents the best tensile properties, with a YS, UTS and elongation of 288 MPa, 371 MPa and 9.4%, respectively. The enhanced tensile properties of TiP/VW94 composites are attributed to the load transfer, grain refinement, dislocation strengthening, dispersion strengthening, and an increase in lamellar LPSO and RE-rich phase with appropriate content and size.