Fe-based sintered matrix for diamond tools: microstructure, mechanical performance and crack initiation and propagation characteristics

To design Fe-Cu-Sn-Ni metal binders for diamond tools and optimize the performance of binders, Fe-based binders were prepared by hot-press sintering method using Fe powder, Cu powder, Sn powder and Ni powder as the raw materials. The phase constitution, microstructure, mechanical properties and crack formation were evaluated. Results showed that Fe-based matrixes are composed of Cu 3 Sn intermetallic compounds and several solid solutions, such as α -Fe, γ (Fe,Ni), and Cu 13.7 Sn. The relative high Sn content can increase the hardness of the sintered bulk samples and significantly reduce the bending strength. With the increase of Ni content, the hardness increases gradually, while the bending strength increases firstly and then decreases. The cracks initiate from brittle Cu 3 Sn intermetallic phases and quickly propagate in the brittle phases or along the interface between Cu 3 Sn intermetallic compounds and γ (Fe,Ni) phases. The propagation of crack can be impeded by Cu 13.7 Sn solid solution.