Laves phase precipitation in Ti-Zr-Fe-Cr alloys with high strength and large plasticity

In this work, a novel serial of Ti-33Zr-xFe-yCr (x=3, 5, 7 wt% and y=2, 4wt%) alloys was designed first with an expectation to obtain Laves phase inmicrostructure and then these alloyswere produced using cold crucible levitation melting. Microstructure and phase analyses suggest the precipitation of a C15 type Laves phase with a dominating beta phase in all the Ti-33Zr-xFe-yCr alloys except in Ti-33Zr-3Fe-2Cr alloy which has a single beta phasemicrostructure. The volume fraction of the Laves phase increases upon increasing the Fe and Cr concentrations in Ti-Zr-Fe-Cr alloys. Mechanical properties evaluation reveals the highest ultimate compressive strength (similar to 2 GPa) and superior plastic strain (33.6%) in Ti-33Zr-3Fe-4Cr alloy. Moreover, all the studied alloys exhibit extraordinarily high yield strength above 1 GPa and hardness exceeding 8 GPa. Embrittlement in Laves phase alloys, which is a common problem, is not encountered in thiswork as all the studied alloys display plastic strain including maximum elongation of 40%. The fracture behaviour of each studied alloy is also discussed in terms of the influence of Laves phase on a fracture, shear banding pattern and plastic deformation. (C) 2018 Elsevier Ltd. All rights reserved.