Correlations between aging heat treatment, ω phase precipitation and mechanical properties of a cast Ti-Nb alloy

Ti-Nb alloys were arc melted in a water-cooled copper hearth in an inert atmosphere. After preparation, the samples were centrifugally cast in copper molds, and rapidly cooled, resulting in a martensitic microstructure. They were then aged at different temperatures. The microstructural characterization of this material suggested that martensite decomposition occurred, leading to precipitation of α, β and ω phases. Aging at higher temperatures led to ω phase decay. Mechanical characterization indicated that the heat treatment enhanced the strength and ductility of the alloys. Correlations between heat treatment, ω precipitation and mechanical behavior are discussed.