Effect of vanadium content on microstructure and properties of in situ TiC reinforced VxFeCoNiCu multi-principal-element alloy matrix composites

Abstract

VxFeCoNiCu high entropy alloy matrix composites reinforced by in situ TiC particles (10 vol.%), i.e., VxFeCoNiCu/TiC composites, were fabricated from V–Fe–Co–Ni–Cu–Ti–C system using vacuum inductive melting method. With the content of vanadium increasing, the size of TiC particles decreased gradually. Meanwhile, vanadium agglomeration occurred slightly. The reaction mechanism of the mixed powder (Fe, V, Ti and C) and the mechanical properties of obtaining VxFeCoNiCu/TiC composites were studied. It was found that three reactions occurred (Fe\u2009+\u2009Ti\u2009→\u2009FeTi\u2009+\u2009Fe2Ti, FeTi\u2009+\u2009Fe2Ti\u2009→\u2009Fe\u2009+\u2009Ti and Ti\u2009+\u2009C\u2009→\u2009TiC) in the heating process. The apparent activation energy for these three reactions was calculated and found to be 26.4, 698.3 and 1879.0\xa0kJ/mol, respectively. At room temperature, tensile strength and elongation increased first and then decreased with the increase in vanadium content and the microhardness increased gradually. The maximum tensile strength of the composites was determined to be 666\xa0MPa, representing a 17.7% increase over that of FeCoNiCu/TiC high entropy alloy composites.