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.