SPS预烧结制备超细晶梯度硬质合金

摘要 首先采用SPS预烧结和真空预烧结制备超细晶硬质合金，再经过梯度烧结使超细晶硬质合金表面形成梯度层，研究了不同预烧结方式对合金组织的影响，分析了预烧结后合金微观组织对超细晶硬质合金的梯度形成及晶粒生长的影响.结果表明，预烧结后合金的微观组织对梯度烧结后的梯度形成和晶粒生长有较大影响，经过SPS预烧结后的硬质合金进行梯度烧结后，可以获得梯度层厚度为 53μm，平均WC晶粒尺寸为0.3μm的超细晶梯度硬质合金.
Abstract：The ultrafine-grained gradient cemented carbide (UGCC) was prepared by a two-step sintering， containing spark plasma or vacuum pre-sintering， and a gradient sintering. The effect of the pre-sintering mode (spark plasma or vacuum)on microstructure of the UGCC is studied and the influence of the pre-sintered microstructure on the gradient formation and grain growth during gradient sintering process is also analyzed. The results show that the pre-sintered microstructure of the UGCC greatly affects the gradient formation and grain growth during gradient sintering. Using this two-step sintering， the thickness of gradient layer of the UGCC can be increased to 53μm， associated with the average grain size of WC about 0.3μm.