Influence of vacuum hot-pressing temperature on the microstructure and mechanical properties of Ti-3Al-2.5V alloy obtained by blended elemental and master alloy addition powders

This study addresses the processing of near-net-shape, chemically homogeneous and fine-grained Ti-3Al-2.5V components using vacuum hot-pressing. Two Ti-3Al-2.5V starting powders were considered. On one side, hydride-dehydride (HDH) elemental titanium was blended with an HDH Ti-6Al-4V prealloyed powder. On the other side, an Al:V master alloy was added to the HDH elemental titanium powder. The powders were processed applying a uniaxial pressure of 30 MPa. The sintering temperatures studied varied between 900 degrees C and 1300 degrees C. The relative density of the samples increased with processing temperature and almost fully dense materials were obtained. The increase of the sintering temperature led also to a strong reaction between the titanium powders and the processing tools. This phenomenon occurred particularly with boron nitride (BN) coating, which was used to prevent the direct contact between titanium and graphite tools. The flexural properties of the Ti-3Al-2.5V samples increased with vacuum hot-pressing temperature and are comparable to those specified for wrought titanium medical devices. Therefore, the produced materials are promising candidates for load bearing applications as implant materials. (C) 2012 Elsevier B.V. All rights reserved.