Texture and Microstructure Variation in Severe Plastic Deformed OFHC Cu Wires

Abstract

The texture and microstructure resulting from heavily drawn and annealed oxygen-free high conducting (OFHC) copper wires have been investigated using several microscopical techniques including orientation imaging microscopy and nano-indentation. In the as-drawn condition, the microstructure and texture were heterogeneous across the wires, and consisted of three distinct concentric regimes: the inner core, the mid section, and the outer region. Whilst the microtexture of the inner core was dominated by a strong <111>+weak<100> duplex fiber texture, the mid section and the outer region had a comparatively weak fiber texture. Analysis using a Taylor-type viscoplasticity model revealed that the weak texture observed in this material was a direct consequence of shear deformation during drawing. The recrystallization kinetics of the wires upon isothermal annealing at various temperature was influenced by the deformation heterogeneity, and can be accurately described by a modified JMAK-Microhardness model. In this approach, the JMAK model is expressed in terms of microhardness data, from which the parameters of the different restoration kinetics were determined.