D-Optimal Mixture Design of Fe-Based Pre-Alloyed Diamond Bit Matrix with Low Liquid Phase Content

To explore a new formulation system of diamond bit matrix, three kinds of Fe-based pre-alloyed powder with low liquid phase content were utilized for the matrix fabrication of impregnated diamond bit (IDB). To this end, the D-optimal mixture design method was employed for the design of the experiment scheme which contained 16 groups of samples. The samples were fabricated under the same hot pressing sintering conditions, then tests on hardness, bending strength, and relative density were conducted. The results were analyzed by regression analysis, and so were the interrelations and interactions of formula components on matrix properties. Meanwhile, the fracture surface of samples after the bending strength test was observed by SEM. It was found that FAM1020 and FAM2120 have a positive effect on the bending strength of metal matrix composite. Besides, FAM2120 has a positive effect on the hardness of the matrix, but a negative effect on the bending strength of the diamond matrix composite. The interaction among the three powders can improve the performance of the matrix. According to the result, the Fe-based pre-alloyed bit matrix with low liquid phase content can meet the requirements of the diamond bit matrix. Based on this exploration experiment, an optimal formulation is concluded as 50 wt % X1, 30 wt % X2, 20 wt % X3.