Interfacial stability of regenerated moulds against molten ZTC4 alloy

Aimed at the effect rules of several typical metal ions from reclaimed shells on contaminating casting surface, with the method of adding metallic elements such as Al, Nb and Mn to shell materials used to actually cast ZTC4 alloy (Ti-6Al-4V), this study analyzed the influence of different residual metals in casting process on casting surface quality, ceramic/titanium alloy interaction compositions, microstructure morphology and micro-hardness, and discussed the impact of residual casting metal in recycled mould materials on the interface stability between ceramic mould and new titanium alloy cast. The results show that the cast surface of ZTC4 alloy using moulds containing Al, Nb or Mn ions looks smooth with no obvious casting defects; compared with none metal containing mould, the roughness of ZTC4 cast using shells with residual metal increases markedly; Al vestigital had little effect on the interface inertness of ceramic against molten titanium alloy, while Nb and Mn can obviously reduce the interface inertness, and to some degree, casting surface roughness can reflect the interface stability; when the mould contains Al, Ti₅Si₃ phase is found at ceramic/metal interface.