Growth order and activation energies for grain growth of Ti [sbnd]6Al [sbnd]4V alloy in ß phase

Abstract

This paper reports that one of the reasons usually stated for avoiding annealing treatments and hot working of Ti-6Al-4V alloy at temperatures over the {beta} transus is the large grain growth which takes place at such temperatures. The aim of the present work is to quantify the grain growth kinetics when the alloy is heat treated in its {beta} phase. It is well known that the driving force for grain growth comes from the surface energy of the grain boundaries. When thermal energy is given to the material, diffusion takes place which leads to grain selection. This means that the number of grains decreases, their size increases, the area of the grain boundaries decreases with the total energy stored in them and consequently a state of higher thermodynamic stability is reached.