Abstract
The growth of the modulated structure during isothermal aging and the influence of the growth on the yield stress of aged Cu-5 at%Ti alloy was investigated. The wave lengths and amplitudes of the modulated structure were obtained from angular distances between the side band and the matrix reflections and from the ratio of reflection intensities of the side band to the main reflection, respectively. The results obtained are as follows: (1) In the early stages of aging, Cu-5 at% Ti alloys have a modulated structure, the wave length and the amplitude of which increase continuously with aging. (2) Experimental results of the yield stresses of the alloys in the early stages of aging seem to support Cahn’s theory based on an interaction between a dislocation and the sinusoidal internal stress fields due to the compositional modulation. In the later stages of the structural modulation, the yield stress is smaller than Cahn’s theoretical values. This disagreement is considered to be caused by the change of the structure from the sinusoidal to rectangular distributions.
