but Morrison model has been developed for steels, in the case of titanium alloys with predominant alpha phase (HCP), the alloy exhibits different work hardening behavior as a result of crystallographic texture.
As a rule, high-strength materials have lower (n) values than low-strength materials. the exponent (n), is a measure of the persistence of hardening. If (n) is low, the work-hardening rate is initially high but the rate decreases rapidly with strain. On the other hand, with a large (n), the initial work-hardening is less rapid but continues to high strains. from previews the strain hardening increase with increasing grain size.
Reference///
William F. Hosford, " Solid Mechanics ", Published in the United States of America by Cambridge University Press, New York, 2010.PP. 59