Interfacial reactions between Ti-1100 alloy and ceramic mould during investment casting

The characteristics of the interfacial reaction between Ti-1100 melt and different primary coating materials was investigate. The effect of refractory materials and mould temperature on the reaction was analyzed by comparing the thickness, distribution of elements and microhardness of α-case layer. The α-case layer thickness of Ti-1100 casting with ZrO₂ primary coating is approximately 38 μm, which is higher than that with Y ₂O₃ primary coating (18 μm). Ti-1100 casting using ZrO₂ primary coating shows higher surface microhardness than that using Y₂O₃ primary coating. The higher mold temperature results in more severe interfacial reaction. With the same primary coating material and mould temperature, Ti6Al4V alloy presents better stability than Ti-1100 alloy.