预合金粉含量对铁基胎体微观组织及性能的影响

研究添加2%、6%、10%和14%质量分数的CuZnSn预合金粉，对金刚石陶瓷磨边轮铁基胎体热压烧结组织、物相组成及力学性能的影响。结果表明:不添加预合金粉烧结的铁基胎体主要包括灰白色、浅灰色和深灰色3种组织，存在的物相主要为γ-Fe、(Cu, Sn)和(γ-Fe, Ni)固溶体以及Fe₄Cu₃、Cu₄₁Sn₁₁、Ni₄Sn等金属间化合物；加入预合金粉后，烧结工艺相同时，胎体中灰白色组织面积明显减少，浅灰色组织面积增加，深灰色组织面积变化不明显，除上述物相外，还出现了Cu_0.61Zn_0.39和CuZn₂物相。随着CuZnSn预合金粉含量增加，铁基胎体的致密度、硬度、抗弯强度均呈先增大后减小的趋势，而磨损量则呈先减少后增加的趋势；在CuZnSn添加质量分数为6%时，分别达到最大值99.8%、104.4 HRB、947.2 MPa和最小值0.272 5 g。添加适量CuZnSn预合金粉可以增加铁基胎体的液相量，改善粉体流动性，提高胎体性能，添加过量则会降低其综合性能。 

Influence of pre-alloyed powder content on microstructure and properties of iron-based matrix

The effects of adding CuZnSn pre-alloyed powder, mass fractions of which were 2%, 6%, 10% and 14%, respectively, on some performances of the iron-based matrix of the diamond ceramic edging wheel were studied, namely the hot-pressed sintering structures, the phase compositions and the mechanical properties. The results show that the iron-based matrix without pre-alloyed powder mainly consists of three kinds of structures: gray-white, light gray and dark gray. The main phases are γ-Fe, (Cu, Sn), (γ-Fe, Ni) solid solution and Fe₄Cu₃、Cu₄₁Sn₁₁ and Ni₄Sn intermetallic compounds. When the matrix with pre-alloyed powder added are sintered at the same conditions, the gray-white structure area decreases with increasing light gray structure area and stable dark gray structure area. In addition to the above phases, Cu_0.61Zn_0.39 and CuZn₂ are also found. With the increase of CuZnSn pre-alloyed powder content, the density, the hardness and the bending strength of iron-based matrix increase first and then decrease, while the wear amount decreases first and then increases. When the mass fraction of CuZnSn pre-alloyed powder is 6%, the maximum values are 99.8%, 104.4 HRB, 947.2 MPa and the minimum value is 0.272 5 g, respectively. Adding appropriate amount of CuZnSn pre-alloyed powder can increase the liquid content of the iron-based matrix, which improves the fluidity of the powder and then the properties of the matrix. However, excessive CuZnSn pre-alloy powder would reduce the comprehensive properties of the matrix.