Evolution And Effect Of Crystallographic Texture In Cu-Ag Filamentary Microcomposites

Cu-6% Ag and Cu-12% Ag strengthened by the double-phase filamentary composites were prepared by heavy drawing and annealing at different temperatures. The intensity and distribution of crystal texture in both Cu and Ag phases were investigated for the composites under the conditions of different drawing ratio, and the effect of annealing temperature on the intensity and distribution of crystal texture was also investigated by annealing the composites at different temperatures. The effect of Ag content on the intensity and distribution of deformation texture was discussed by analyzing the characteristic of deformation texture of both Cu and Ag phases in Cu-6% Ag and Cu-12% Ag. Besides, the effect of texture intensity on elastic modulus of Cu-12% Ag alloy was investigated.In both Cu and Ag phases, <111> component can be preferentially formed during the evolution of as-cast microstructure into filamentary morphology. There are also <100> and <211> components in Cu phase besides <111> component. The texture intensity increases with increasing drawing strain and can reach a maximum at a certain draw ratio. Once drawing strain is higher than the certain draw ratio, the intensities of <100> and <211> components in Cu phase maintain an approximate constant but the intensity of <111> component decreases in both Cu and Ag phases.The change of crystal orientation induced by dislocation glide on slip planes is mainly responsible for the change of texture distribution in the range of lower drawing strain. However, interface shearing can play an important role in remodifying crystal orientation or varying texture distribution as drawing strain exceeds a certain degree.With the increase of annealing temperature up to 400℃, the <111> component intensity decreases and the <100> component intensity increases in Cu phase while the <111> component intensity in Ag phase changes insignificantly. Annealing at temperatures higher than 400℃ enhances the texture intensities in both Cu and Ag phases. The texture formed by heavy drawing in Ag phase is more stable than that in Cu phase for the composite annealed at lower temperatures. The interface migrating,structure aggregating, fiber glomerating, and grain propagating from recover and recrystallization in annealing process generally change the intensities of the texture components formed by heavy drawing to form annealing texture. Therefore, the annealing texture components have the same orientation indexes as the deformation texture components.Due to the difference of eutectic quantity in initial structure of the two alloys with different Ag content, the relative quantity of different kinds of interface is different, which ultimately results in the difference of texture intensity of the two alloys. The components of deformation texture in Cu-6% Ag are similar to those in Cu-12% Ag under the condition of the same drawing ratio. However, the intensity of <111> component of Cu phase in Cu-6% Ag is higher than that in Cu-12% Ag, and the intensity of <111> component of Ag phase in Cu-6% Ag is lower than that in Cu-12% Ag.The distribution and intensity of deformation texture is one of the most important factors influencing elastic modulus of Cu-12% Ag alloy. However, due to the fact that other influencing factors also exist in drawing process, there is no regular relationship between elastic modulus and texture intensity. Because reversion and recrystallization in annealing process can significantly change the elastic modulus of the alloy, the variation of texture intensity is not one of the important fators influencing elastic modulus.