Influence of Structural Modulation on Yield Stress of Cu-5 at%Ti Alloy

Abstract

The isothermal growth of the modulated structure and the structural dependence for the yield stress of aged Cu-5 at%Ti alloys were investigated by the X-ray diffraction method and the tensile test.
(1) In an early stage of aging, Cu-5 at%Ti alloys have modulated structures, the wave length and amplitude of which increase continuously on aging.
(2) Experimental results on the yield stresses of Cu-5 at%Ti alloys in an early stage of aging seem to support Cahn’s theory, in which the interaction between a dislocation and the periodic internal stress field due to compositional modulation is considered. In the later stage of structural modulation, yield stresses are lower than Cahn’s theoretical values. This may be due to the fact that the distribution of solute atoms in the modulated structure changes into the rectangular one.