PORTEVIN–LE CHÂTELIER INSTABILITY IN L10-TiAl SINGLE CRYSTAL

Abstract

We studied the deformation behaviour of γ Ti -54.5% Al single crystal at temperatures ranging from 200°C to 700°C along [153] orientation, where the major operative slip system is [Formula: see text]. During this temperature regime, deformation microstructure consists of long heavily pinned screw dislocations. Serrated plastic flow has been observed at 500°C, the serration amplitude decreases with strain. The combination of the strain ageing and stress relaxation experimental results demonstrate for the first time the Portevin–Le Châtelier type instability in TiAl single crystal.