Structure and Physicomechanical Properties of Cast Titanium Alloys of the Ti-Nb-Mo System

摘要

Ternary alloys of the Ti-Nb-Mo system are obtained by the method of arc remelting with subsequent crystallization on a copper water-cooled hearth. In these alloys characterized by contents of alloying elements corresponding to the molybdenum equivalent (Moeqv) within the range 3.2-4.0, we observe the formation of hexagonal (alpha ') and orthorhombic (alpha '' ) martensites. For higher Moeqv (4.6), we detect the appearance of a phase based on beta -titanium instead of the orthorhombic martensite. In all analyzed alloys, we do not reveal the acicular microstructures characteristic of martensites. In these alloys, the (beta -Ti) phase has higher hardness and Young's modulus as compared with alpha ' and alpha ''. The Ti94Nb4Mo2 and Ti(92.5)Nb5Mo(2.5) as-cast alloys are characterized by low Young's moduli (similar to 70 GPa).