烧结工艺对脱β层梯度硬质合金梯度结构的影响
Effect of sintering procedures on the gradient structure of graded cemented carbides with a cubic carbide-free layer
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摘要: 使用一步烧结法制备了表面含脱β层的梯度结构硬质合金,采用扫描电镜、X射线衍射仪、电子探针微区分析仪观察了梯度硬质合金的微观形貌、相组成及成分分布情况,分析了脱β层梯度结构合金样品的典型组织及烧结工艺对脱β层梯度硬质合金梯度结构的影响.结果显示:随着烧结温度的提高和保温时间的延长,脱β层的厚度均明显增加,且脱β层的厚度与保温时间的平方根基本呈线性关系;在同样的烧结工艺条件下,脱β层的厚度随着钴含量的增加而增大,随Ti(C,N)含量的增加而减小.Abstract: Graded cemented carbides with a cubic carbide-free layer(CCFL) in the surface were synthesized by one-step sintering.The microstructure,phase composition and element distribution of the graded cemented carbides were investigated by scanning electron microscopy,X-ray diffraction analysis and electron probe microanalyzer,respectively.The typical microstructure of the graded cemented carbides and the effect of sintering procedures on gradient structures in the graded cemented carbides were discussed in detail.It is shown that the depth of CCFL significantly increases with increasing sintering temperature and prolonging holding time,and there exists a linear dependence approximately between the depth of CCFL and the square root of holding time.The depth of CCFL becomes larger at a higher cobalt content,but narrows with increasing Ti(C,N) content for the same sintering procedure.