Structure and mechanical properties of Ti-6Al-4V alloy after zirconium addition

In this paper, zirconium (Zr) is selected as a partial substitutable element for titanium (Ti) in Ti-6Al-4V (TC4) alloy to fabricate series of TiZrAlV quaternary alloys. Mechanical testing, microhardness testing, metallographic analysis, X-ray diffraction, and fracture analysis are performed to evaluate the microstructure and mechanical properties of the alloys. The tensile strength and microhardness are found to increase with increased Zr content, whereas the elongation ratio decreases with gradually increased Zr content. The morphology of alpha phase suffers a series of changes with the increase of Zr content. The beta phase contents of the alloys studied also gradually increase with the increase of Zr content. Ti-20Zr-6Al-4V alloy, which has outstanding mechanical properties (sigma(b) = 1.317 MPa and delta = 8%), is found to be the best composition. Hence, a series of new quaternary alloys has potential uses in the nuclear and aerospace industries as structural materials. (C) 2012 Elsevier B.V. All rights reserved.