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

In order to study the deformation characteristic of the two-phase titanium alloy at the microlevel, the stress-strain relationship of primary alpha phase (alpha(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 beta matrix (beta(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 alpha(p), the contribution rate of alpha(p) to macro-stress tends to decline, while the contribution rate to macro-strain tends to ascend.