Effect of Fe-based pre-alloyed powder on the microstructure and holding strength of impregnated diamond bit matrix. (February 2019)

• Record Type: Journal Article
• Authors: Zhao, Xiaojun; Li, Jingyi; Duan, Longchen; Tan, Songcheng; Fang, Xiaohong
• Is Part Of: International journal of refractory metals & hard materials. Volume 79(2019)
• Page Start: 115
• Page End: 122
• Publication Date: 2019-02
• Subjects: Pre-alloying degree -- Sintering temperature -- Relative density -- Holding force coefficient -- Bending strength -- Fracture morphology; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2018.11.015
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: An iron-rich pre-alloyed powder was selected out, and the pre-alloying degree of matrix materials and the sintering temperature were considered to investigate the effect of the Fe-based pre-alloyed powder on the microstructure and holding strength of impregnated diamond bit matrix. And relative density and bending strength of the specimens were measured, and then the resulting fracture surfaces were analyzed using scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The results showed that the relative density, bending strength and plasticity of matrix materials are increased with the sintering temperature and the pre-alloying degree. The influence of the pre-alloying degree on them is more significant than that of the sintering temperature within the experimental parameters. Besides, Fe-based matrices have thermal corrosion effect on diamonds at high temperature sintering process. And the rate of diamond graphitization has a greatly increase with the sintering temperature changes from 900 °C to 1020 °C and the holding strength decreases. A low pre-alloying degree accelerates the rate of diamond graphitization. But an adequate pre-alloying degree of Fe-based matrix materials is conducive to improve the wettability of the matrix to diamonds, alleviate the diamond graphitization, reduce the diamonds' thermal damage and improve the holding strength. Besides, it can also greatly reduce the sintering temperature and broaden the sintering temperature range. In a word, it is feasible and reasonable that Fe-based pre-alloyed powders replace Fe elemental powders to fabricate impregnated diamond bits. And it has a good economic value and broad application prospect. Highlights: The relative density, bending strength and plasticity of the matrix were studied. They are increased with the sintering temperature and the pre-alloying degree. A low pre-alloying degree accelerates the rate of diamond graphitization. A high pre-alloying degree reduces the graphitization and improves the holding force. It can also greatly reduce the sintering temperature and broaden the sintering range.