Improvement in the Mechanical Properties of AlNbTiVCrNi_1.5 High Entropy Alloys Containing Alloyed C

Lightweight high entropy alloys with various Ni and C contents were prepared by vacuum arc melting. The cooperative effects of Ni and C additions on the phase formation, microstructure and mechanical properties. The results shows that The Ni1.5 (AlNbTiVCr) 98.5-xCx (at. %) high entropy alloys are composed of BCC matrix phase, TiC phase, C14 Laves phase, and a small amount of C15 Laves phase. The microstructure of alloys is a typical dendritic structure, with TiC distributed between the dendrites and needle like C14 Laves phase dispersed within the dendrites. The addition of C increases the mechanical properties of alloys first and then decreases. Ni1.5AlNbTiVCrC1 alloy shows the best mechanical properties, and its compressive strength and fracture strain are 1968.1 MPa and 13.7 %, respectively. The improvement in mechanical properties of lightweight high entropy alloys is attributed to solid solution strengthening and second phase strengthening.