W对自由烧结型铁基金刚石工具胎体性能的影响

摘要

以专用于自由烧结型金刚石工具胎体的亚微米级铁基合金粉末为主要结合剂，添加金属 W(添加量为0~12%，质量分数)，采用自由烧结工艺制成金刚石工具胎体和金刚石/胎体试样，对胎体进行力学性能测试和断口形貌分析，并用金刚石工具进行磨削试验。结果表明，随 W 含量增加，胎体的相对密度及强度均下降；添加6.0%W可明显提高胎体对金刚石的把持能力，并提高胎体硬度，但随W含量进一步增加，把持能力下降，同时胎体硬度降低；W在胎体内虽然可生成强碳化物，但在自由烧结过程中起不到强化胎体的作用，反而降低胎体的韧性，尤其是当胎体中添加12.0%W时，胎体内孔隙明显，强度大幅下降；与不添加W的胎体相比，添加8.0%W时，虽然金刚石工具的锋利度有所下降，但耐磨性提高。%Using specially 0−12%in mass fraction prepared sub-micron Fe based alloy powder as main binder in matrix of free sintering diamond tools and adding metal W in matrix, the standard specimen matrixes were prepared by free sintering process. The mechanical properties test, fracture morphology analysis and grinding test were carried out. The results show that the relative density and strength of the matrix decrease with increasing W content in the matrix. The holding ability of matrixes for diamond and the hardness of the matrix increases obviously when W content is 6.0%, but decreases simultaneously when the W content is over this point. Although strong carbide in the matrix can be generated by W, but the matrix can not be strengthened and the toughness ability is lower. Pores appear obviously in matrix and the strength of matrix decreases sharply when W content in the matrix increases to 12.0%. Compare with the diamond tools matrix without W, the abrasion ability of diamond tools can be improved by adding 8.0%of W while the sharpness of diamond tools decreases.