The Transverse-Rupture Strength of Ti(C, N)-Mo₂C-Ni Alloys Affected by Nitrogen Content and Particle Size

The room temperature transverse-rupture strength (TRS) of nitrogen contained cermets was studied in relation to the nitrogen content and particle size. The TiC-, TiC_0.7N_0.3- and TiC_0.5N_0.5- 10.0 vol%Mo₂C-16.4 vol%Ni alloys HIP-treated and then resintered were used as the specimens. The resintering process employed here was to eliminate the nickel pools often developed in nitrogen contained alloys, when HIP-treated. The TRS of the nitrogen contained alloys had a tendency to increase with decreasing particle size of carbonitrides, because the defect size decreased with the particle size. The intrinsic strength of the nitrogen contained alloys showed a maximum of about 6.0 GPa at the particle size of 1.0 pm. The TRS as high as 3.2 GPa or more was observed when the particle size became 0.5∼0.8 μm. It was suggested that the strength of nitrogen contained alloys could be increased further with decreasing defect size.