Effect of cooling rate on Ti–Cu eutectoid alloy microstructure

Titanium alloys present a combination of properties that makes them suitable materials for various medical applications, and there is special interest in Ti–Cu alloys for the fabrication of dental prostheses. The addition of Cu to Ti lowers the melting point of the alloy, as well as leading to the development of desirable mechanical properties. In this study a eutectoid alloy was prepared and heat treated, then cooled at various cooling rates. The eutectoid structure (α + Ti 2Cu) was observed for all cooling rates used, and evidence of α′ martensite was found for cooling rate higher than 9 °C s –1. Lower cooling rates resulted in higher modulus values. This was attributed to the volume fraction of the α and Ti 2Cu phases. Higher cooling rates produced structures with lower modulus values and greater hardness, a result attributed mainly to the development of a martensitic structure.