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粗晶硬质合金由于高导热率、高强度及耐冲击等性能而被广泛应用于采掘钻探等.本文通过固体渗碳制备粗晶功能梯度硬质合金,研究制备粗晶功能梯度硬质合金的不同渗碳参数,探索渗碳工艺与合金显微组织及力学性能的关系.研究发现,在不同的渗碳温度下,粗晶硬质合金渗碳效率均较低,梯度层形成缓慢;低于1 440℃,渗碳反应及扩散较慢,难以制备获得功能梯度硬质合金.超过1 450℃,可以通过固体渗碳获得功能梯度硬质合金.当温度达到1 450℃后,继续提高温度对合金梯度层的形成影响不大;而延长时间却可以使其渗碳反应得到充分进行,梯度层提高明显.同时,稀土Y2O3在粗晶功能梯度硬质合金中对梯度层形成、晶粒抑制作用及其力学性能的影响均较为有限;随渗碳温度升高,其添加效果减弱.“,”The cemented carbide with coarse grain is widely used in mining drilling due to high thermal conductivity,high strength and impact resistance and so on.Functionally graded cemented carbide with coarse grain was prepared by solid carburizing in this research.The different carburizing process was studied,and the relationship between carburizing process and the microstructure,mechanical properties were studied.Meanwhile,the role of rare earth was researched in functionally graded cemented carbide with coarse grain.Results show that the carburizing efficiency of coarse grain cemented carbide is low and the formation of gradient layer is slow at different carburizing temperatures.When the carburizing temperature is lower than 1 440 ℃,it is difficult to prepare the functional gradient cemented carbide.When higher than 1 450 ℃,functional gradient cemented carbide can be formed by solid carburizing.Further increase of temperature has little effect on the formation of gradient layer when the temperature reaches 1450 ℃,but the carburizing reaction can be fully carried out by prolonging carburizing time and the gradient layer is improved obviously.The influence of Y2O3 on the formation of gradient layer is limited for the coarse grain cemented carbide and the effect decreases with the increase of carburizing temperature.