Effect of cold severe deformation by multi directional forging on elastic modulus of multi functional Ti+25 mol% (Ta,Nb,V) plus (Zr,Hr,O) alloy

A new and unique beta-titanium alloy (Ti + 25 mol% (Ta,Nb,V) + (Zr,Hr,O) has interesting properties such as low elastic modulus, high strength and high elastic deformability as well as Invar and Elinvar properties. These properties have been successfully realized for the round wire or rods by cold working process but not enough for the sheet made by the cold rolling. To improve the mechanical properties of the alloy sheet, the effect of cold severe deformation on the elastic modulus and microstructure of the alloy sheet was experimentally investigated. The samples were processed using the multi directional forging (MDF) and cold plain rolling. The elastic modulus of the alloy sheet which was cold rolled after MDF was lower than that of cold rolled sheet without MDF. The severe cold plastic deformation by MDF was also effective for obtaining isotropic elastic modulus and very fine grain size (similar to 1 mu m) of sheet after plain rolling. The prototype sheet with low elastic modulus (60-65 GPa), high strength (1100 MPa) and high ductility (total elongation more than 10%) was successfully made in the laboratory test by combining MDF and plain rolling at room temperature. (C) 2009 Elsevier Ltd. All rights reserved.