Superplastic forming of Ti6Al4V alloy using ZrO 2-TiO 2 ceramic die with adjustable linear thermal expansion coefficient

Abstract

Firstly, the relation between the coefficient of thermal expansion(CTE) and the volume fraction of TiO 2 was investigated, and also the influence of relative density of ceramic on the CTE was studied. The results show that the volume fraction of TiO 2 and the relative density both make influence on the CTE of ZrO 2-TiO 2 ceramic. According to the results, the ZrO 2-TiO 2 (volume fraction of TiO 2 is 27%) ceramic die with the similar CTE (8.92×10 −6 °C −1) to Ti6Al4V was fabricated. Secondly, to evaluate the dimensional accuracy of the workpiece superplastically formed, the Ti6Al4V impression experiment was performed. The result shows that the dimensional inaccuracy of workpiece is 0.003. Thirdly, in order to evaluate the practicability, the experiment of superplastic forming Ti6Al4V using ZrO 2-TiO 2 cylinder ceramic die was carried out. The Ti6Al4V cylinder shows good shape retention and surface quality, and high dimensional accuracy. The ceramic dies seem to be adequate for superplastic forming the high accuracy Ti6Al4V, and the trials have confirmed the potential of the ZrO 2-TiO 2 ceramic die.