| Because of excellent comprehensive properties, Cu-Cr-Zr alloy is widely appliedin casting crystallizer, integrated circuit lead frame, contact wire of electrified train,etc. At present, the researches on hot deformation behavior of Cu-Cr-Zr series alloyhave been rarely reported, and there is no consensus of concept as to the precipitatecrystalline structure.In this work, the flow stress change rules and plastic deformation behaviors of theCu-Cr-Zr-RE alloys during hot compression deformation were studied by theisothermal compression test at a Gleeble-1500D thermal-mechanical simulator. Basedon the results, both the hot deformation activation energy Q and the constitutiveequation were determined, the dynamic materials model (DMM) processing mapswere also established. The critical conditions of the dynamic recrystallization of theCu-Cr-Zr-Y alloy were investigated. After being deformed in different degrees, thesolid soluted Cu-Cr-Zr and Cu-Cr-Zr-Y(Ce) alloys were aged at250℃~400℃fordifferent holding time. The effects of cold deformation and aging temperature on themicrohardness, electrical conductivity and precipitate structure and morphologywere studied, respectively.The results show that: According to the true stress-true strain curves of the Cu-Cr-Zr and Cu-Cr-Zr-Y(Ce) alloys during hot compression deformation, the softeningmechanisms were identified as dynamic recovery and dynamic recrystallization type atdifferent deformation condition, respectively. The hot deformation activation energy Qand constitutive equation of the alloys were derived, respectively. Based on the DMMtheory, the processing maps of the Cu-Cr-Zr and Cu-Cr-Zr-Y(Ce) alloys wereconstructed, respectively. According to both the processing maps and the micro-structure evolution rules of the alloys, the optimal processing parameters of hotworking of the Cu-Cr-Zr and Cu-Cr-Zr-Y(Ce) alloys were also proposed. The critical conditions of dynamic recrystallization were attained based on the θ-σ model. Becauseof the addition of rare element Y, the dynamic recrystallization was easyly to takeplace than that of without addition of Y. The higher the aging temperature, and thegreater the deformation degrees before aging treatment, the easier the second phasesprecipitated, resulting in the more excellent comprehensive properties of the alloys.Because of the addition of Y and Ce respectively, the microhardness increases, butthe electrical conductivity decreases. The precipitate of the coherent face-centeredcubic Cr-phase apperes in the Cu-Cr-Zr-Y alloy after80%cold deformation andageing at300°C for18hrs, while the precipitates in the Cu-Cr-Zr-Y alloy aged at350°C for8hrs are body-centered cubic Cr phase and Cu4Zr phase. |
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