# University of Melbourne Advanced Materials Report

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

Abstract

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.