Effects of Cr on microstructure, mechanical properties and hydrogen desorption behaviors of ZrTiNbMoCr high entropy alloys

Abstract

Phase constitution, mechanical properties and hydrogen desorption behaviors of the as-cast (ZrTiNbMo)100-xCrx (x = 0, 2, 5, 10, 15, 20) high entropy alloys (HEAs) have been investigated. ZrTiNbMo alloy has a body-centered cubic (BCC) single phase structure, and the Cr addition leads to the formation of Laves phase. The HEAs can be strengthened by Cr addition due to more formation of Laves phase and solution strengthening. Zr20Ti20Nb20Mo20Cr20 HEA shows the maximum Vickers hardness of 564 HV and maximum compressive yield strength of 1479 MPa, respectively. In contrary, the ductility can be retained when x = 2, but obviously decreases with further increasing Cr content. Thermal stability and hydrogen desorption capacity of the hydrogenated HEAs decreases with Cr addition, which may be mainly ascribed to the reduction of cell volume and much less stability of hydrogen atoms in solid solution with increasing Cr content.