Effects of chromium addition on structure and mechanical properties of Ti-10Zr alloy

As-cast Ti-10Zr and a series of Ti-10Zr-xCr (x = 1, 3, 5, 7 and 10 wt.%) alloys prepared by using a dental casting machine were investigated. Commercially pure titanium (c.p. Ti) was used as a control. The experimental results indicated that these alloys obviously had different structures and mechanical properties with the addition of various amounts of Cr. With 3 wt.% Cr, retention of the metastable beta-phase began. When 5 wt.% or more Cr was added, the beta-phase was almost entirely retained with a bcc crystal structure. Moreover, the omega-phase was formed in the alloys containing Cr in amounts between 3 and 7 wt.% The largest quantity of omega-phase and the highest bending modulus were found in the Ti-10Zr-5Cr alloy; however, its bending strength was slightly lower than in alloys containing no omega-phase (Ti-10Zr-1Cr and Ti-10Zr-10Cr) due to premature and brittle fractures. Among all the Ti-10Zr-xCr alloys, only the Ti-10Zr-1Cr and Ti-10Zr-10Cr without an omega-phase exhibited completely ductile properties. Furthermore, the elastically recoverable angles of the Ti-10Zr-1Cr (18.8 degrees) and Ti-10Zr-10Cr (23.8 degrees) alloys were greater than those of c.p. Ti (2.7 degrees) by as much as 590% and 780%, respectively. In the current search for better implant materials, the low modulus, ductile property, excellent elastic recovery capability and reasonably high-strength beta-phase Ti-10Zr-10Cr alloy appears to be a promising candidate. (C) 2009 Elsevier B.V. All rights reserved.