Preparation of Single Crystals of Titanium and their Mode of Deformation

Abstract

SINGLE crystals up to 20 mm. × 2.5 mm. × 1 mm. have been prepared in pure titanium by a modified strain anneal technique. Pure titanium of hardness of 90 V.P.N., indicating 0.01 wt. per cent of oxygen plus nitrogen¹, prepared in this laboratory by the van Arkel process, was first arc-melted² and then cold-rolled with intermediate annealing at 860° C. to strip in which there was very little preferred texture. By suitably gettering the purified argon used as a protective atmosphere throughout this preparation, the hardness of the titanium was not increased. The grain-size of this strip was fairly coarse and uneven (1–25 grains/mm.²). Tensile strains from 0.05 to 5 per cent did not give large crystals on annealing for 90 hr. at 860° C.; but compressive strains between 0.1 and 1 per cent, followed by similar annealing, produced in one-third of the specimens a crystal occupying the whole cross-section and an appreciable part of the gauge length, as illustrated.