Effect of Fe based-pre-alloyed powder content on the pressless sintering behavior of the diamond wire saw bead matrix

To promote the application of pre-alloyed powders in pressureless sintered diamond wire saw beads, Fe-based pre-alloyed powder was employed to substitute pure Fe powder in the matrix. Firstly, six formulations were designed by adjusting the content of pre-alloyed powder and Fe powder based on the original bead formulation. Subsequently, the mechanical properties, microstructural evolution, and diamond retention capability were systematically investigated based on pressureless sintering experiments. The results show that as the Fe based pre-alloyed powder content increases, the three-point bending strength and hardness of the sintered specimens initially decrease and then increase, whereas the strength loss rate exhibits an opposite trend. Optimal comprehensive performance is achieved at a pre-alloyed powder content of 60 wt%, where the sintered matrix exhibits a three-point bending strength of approximately 1800 MPa, a hardness of 108 HRB, and a strength loss rate of 26.5%. SEM and EDS analyses reveal that all six formulations achieve good sintering quality, with relatively dense fracture surfaces free from obvious cracks or voids. Both Fe and Cu-rich regions are observed within the matrix. Furthermore, SEM observations indicate that the pre-alloyed powder exhibits good adhesion to diamond particles during pressureless sintering, however, diamond retention remains predominantly mechanical in nature.