High precision superplastic forming of titanium alloy using ZrO ₂-TiO ₂ ceramic die with controllable linear expansion coefficient

The ZrO ₂-TiO ₂ ceramic die with controllable linear expansion coefficient (LEC) and the high precision superplastic forming were studied. The influence of TiO ₂ fraction and relative density on linear expansion coefficient of ZrO ₂-TiO ₂ ceramic was analyzed. The Turner model was modified and the relative density was introduced into the model. The forming accuracy of ceramic die with the similar LEC to TC4 titanium alloy was measured. The ZrO ₂-TiO ₂ deep cylinder ceramic die was fabricated and its performance was evaluated by the superplastic forming experiment at 925°C. The results show that the LEC decreases with the increment of volume fraction of TiO ₂ and increases with the rising of relative density. The modified Turner model more accurately predicted. Using the ZrO ₂-TiO ₂ ceramic die with optimal LEC, the forming accuracy deviation significantly reduced and not exceed of 0.1%. The ceramic die owns enough sufficient thermal mechanical properties and excellent performance.