University of Melbourne
Advanced Materials Report

Key words \(\alpha\) Nucleation, \(\beta\) Titanium Alloy, Strengthening, Alloying elements


This aim of this report is to discusses the formation of \(\alpha\) particles in the \(\beta\) matrix of titanium alloys with the assitance of athermal \(\omega\) precipitates. It explores the different mechanisms that play a role in the nucleation and growth of \(\alpha\) precipitates as well as further explores the implication of having distributed or clustered \(\alpha\) particles in the solid solution of titanium alloys. This paper analyses the affect of \(\alpha\) precipitates on strength, ductility and toughness and explains the phenomenon using research.

The main findings about the nucleation of \(\alpha\) particles suggest that formation of distributed \(\alpha\) precipitates is assisted by \(\omega\) particles however there are a two different explanation that explain these cases. These speculated reasons are:

  1. 1.

    \(\alpha\) is formed by a displasive method. This method suggests that upon annealing of the alloy containing only athermal \(\omega\) and beta, \(\alpha\) plates begin forming at the core of \(\omega\) precipitates and consequentially displace them

  2. 2.

    Diffusional method, this suggests that due to rejection of alloying elements near \(\omega\) precipitates present in titanium that are \(\alpha\) stabiliser (i.e. Al) \(\alpha\) particles form within close vicinity of the \(\omega\) but not as the core. This phenomenon is used to explain the formation of \(\alpha\) particle at \(\omega\) /\(\beta\) interface. According to the study evidence of both methods are quite prominent and therefore suggests the formation of \(\alpha\) is a mix mode diffusional-displasive method.