Regular Article

Contribution rates of constituent phases to macro-stress and -strain of two-phase titanium alloy

National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004, PR China

^* Corresponding author: pengyan@ysu.edu.cn

Received: 23 February 2017
Received in final form: 21 April 2017
Accepted: 3 May 2017

Abstract

In order to study the deformation characteristic of the two-phase titanium alloy at the microlevel, the stress-strain relationship of primary α phase (α_p) is developed with consideration of geometrically necessary dislocations which are caused by the strain partition between the constituent phases, whereas the stress-strain relationship of transformed β matrix (β_t) is calculated with the data of microindentation tests. Then the modified law of mixture is applied to analyze the contribution rates of constituent phases to macro-stress and -strain. The results show that the contribution rates of constituent phases to macro-stress and -strain are continually changing in the whole deformation process, and they are also affected by the fraction and sizes of the constituent phases. The fraction of each phase is a decisive factor in the contribution rates to macro-stress and -strain. Moreover, when the fraction of each phase is fixed, with the increase of the size of α_p, the contribution rate of α_p to macro-stress tends to decline, while the contribution rate to macro-strain tends to ascend.