Modeling of Densification during Hot Pressing of Fe-Cu-Co-Ni-W-Sn Powder Mixture

The master sintering curve (MSC) is an effective method to predict densification during sintering or hot pressing. In MSC, the sintered density is a unique function of the integral of a temperature function over time, irrespective of the heating path. As a practical application of the MSC, the Fe-based powder mixture consisting of 6 different metallic materials was used since it is one of the most common soft metal-bonds of the diamond tool industry. The effective activation energy of sintering was found to be 200.2 kJ/mol. It suggests that the dominant densification mechanism for the present metallic powder was the diffusion of Cu since the effective activation energy was in good agreement with that of self diffusion in Cu from literature. Three data sets having different heating rates merged onto a single curve when the density was plotted as a logarithmic function of Theta, the integral of temperature function over time. Thus, the density versus Theta profile can be used to predict the final density of Fe-based metallic powder at a given pressure regardless of heating history. The study was also extended to a range of pressures from 9.7 MPa to 58.1 MPa to generate the pressure-assisted master sintering surface (PMSS). [doi:10.2320/matertrans.M2011056]