First-principles study of Hf/Nb/Zr-doped MAX phases Ti3AlC2 and Ti3SiC2

Highlights: • The doping effects of Hf/Nb/Zr on physical properties of Ti3AlC2 and Ti3SiC2 were investigated based on simulations. • Magnetic character was observed in Ti3AlC2 for c-ATi2 site doping of Hf/Zr, which was attributed to electron transfer. • Doping Hf/Nb/Zr at different sites were found to have different effects on Ti3AlC2 and Ti3SiC2. -- Abstract: The effects of doping Hf/Nb/Zr on the structural, electronic, magnetic, mechanical, and thermal properties of Ti₃AlC₂ and Ti₃SiC₂ are investigated based on the density functional theory (DFT). Our calculations show that magnetism can be induced in Ti₃AlC₂ by doping Hf/Zr at c-ATi2 site due to the electron transfer. Doping Hf/Nb/Zr at the Ti1 site has minimal effect on the intrinsic mechanical properties of Ti₃AlC₂ and Ti₃SiC₂, in according with the previous experiment. Whereas doping Hf/Nb/Zr at the interstitial site has adverse effects on the host material, resulting in significantly decreased bulk, shear, Young's moduli and Debye temperature.