Insight into the heterogeneous nucleation mechanism of Ti3AlC2/Mg interface doped with alloying elements by using first principle calculation

Abstract

In the present study, a comprehensive investigation has been conducted on the work of adhesion, interfacial energy, and electronic structure of both pristine and hybrid Ti₃AlC₂(0001)/Mg(0001) interfaces. This examination aims to elucidate the conceptual framework of the interface and explain the heterogeneous nucleation mechanism of Ti₃AlC₂ particles within the Mg matrix composites. Our research reveals a notable discovery: the C(TiC)-terminated Ti₃AlC₂(0001)/Mg(0001) interface, arranged in HCP stacking, demonstrates remarkable interfacial stability. This stability is attributed to the formation of a strong Mg–C covalent bond, which reinforces interfacial bonding strength and durability. Therefore, our findings affirm the potential of Ti₃AlC₂ particles as an effective substrate for heterogeneous nucleation of magnesium grains, ultimately enhancing the strength and ductility of Mg matrix composites. It's worth highlighting that the introduction of specific elements in the layer adjacent to the interface produces significant effects. The incorporation of Fe, Mn, Si, Al, and Ni into the C(TiC)-terminated Ti₃AlC₂(0001)/Mg(0001) interface with HCP stacking significantly boosts adhesion and simultaneously lowers interfacial energy. This beneficial outcome contributes positively to the nucleation process within the Mg matrix. Conversely, the addition of Cu to the interface diminishes adhesion, thereby impeding the nucleation of Ti₃AlC₂ on Mg matrices. Regarding adhesion energy at the alloyed Ti₃AlC₂(0001)/Mg(0001) interface, our analysis ranks the effectiveness of various elements as follows: Fe surpasses Mn, which precedes Si, then Al, succeeded by Ni, and finally Cu. This study significantly advances our comprehension of the distinctive attributes of Ti₃AlC₂(0001)/Mg(0001) interfaces and the fundamental nucleation mechanisms. These insights hold promising potential for advancing the development of innovative magnesium-based composite materials.