Tensile Deformation of Fe-1.5% Ti Alloy Single Crystals Bearing Hydrogen

Abstract

Single crystals of Fe-1.5wt% Ti alloy were grown by single-pass zone melting. As grown crystals and the crystals quenched from hydrogen atmosphere at 800°C were deformed in tension between room temperature and -196°C at a strain rate of 1.67×10^-4 sec^-1. The quenched crystals showed a prominent yielding phenomenon and localized deformation. At room temperature the yield stress of the crystals quenched from hydrogen atmosphere was approximately twice as that of as-grown crystals.
The yielding phenomenon, subsequent work softening, and solid solution softening were discussed as the effect of the hydrogen clusters around substitutional Ti atoms.
A low temperature aging test was done in order to obtain the information about the yielding phenomenon and hardening mechanism. The yield stress of the crystals quenched from hydrogen atmosphere was decreased rapidly by the low temperature aging process.
It was concluded that hydrogen clusters around substitutional Ti atoms cause these phenomena.