Instability of Titanium and Ti/6AL/4V Alloy at Room Temperature

摘要

Titanium and Ti/6Al/4V under torsion exhibit unusual instability which shows itself as (a) abnormally prolonged creep on yielding, (b) ineffective strain-hardening after yielding, and (c) deviations from elastic strain at loads above a limit of proportionality which is low compared with the bulk yield stress. As a result of this inherent instability it is possible to produce significant axial extensions under low tensile stresses combined with small-amplitude cyclic torsion; and to reduce the nominal bulk yield stress in torsion to at least half its nominal value by suitable prior straining. (Author)