Microstructure and mechanical properties of hybrid graphene nanoplatelets/titanium particles reinforced AZ91 laminated composite

Abstract

In the present study, the microstructure and mechanical behaviors of graphene nanoplatelets (GNPs)/titanium (Ti) particles reinforced AZ91 laminate under tension along the rolling direction (RD) were systematically studied. The laminated composite with hybrid GNPs + Ti particles exhibits optimal mechanical properties, with a yield strength of 160 MPa, an ultimate tensile strength of 243 MPa, and elongation of 20.8%. Electron backscattered diffraction and slip trace analysis was conducted to reveal the mechanisms for the enhancement of strength and ductility of AZ91 by GNPs/Ti particles addition. The higher yield strength of reinforced AZ91 composites beyond the un-reinforced AZ91 laminate is mainly derived from the weakened recrystallization behavior near the interfaces by composites layers, leading to strong texture strengthening. The significantly increased ductility is derived from the higher activity of 2nd order pyramidal <c+a> slip and higher energy required for crack generation and propagation by introducing reinforcement layers. Furthermore, fracture observation revealed that introducing Ti particles improved the composite's interlayer bonding properties compared with the GNPs/AZ91 composite, leading to a slight improvement in elongation. This work provides insights into the deformation mechanisms of reinforced, laminated composites, and suggests that a low-cost and straightforward processing method can be employed to fabricate structural materials.