硬质相含量对Ti(C,N)-304不锈钢金属陶瓷力学性能的影响

The effects of Ti(C,N) content on microstructure and mechanical properties of Ti(C,N)-304 stainless steel cermet are analyzed. Scanning electron microscopy and transmission electron microscopy are adopted to observe the microstructures, fracture morphology, crack propagation and microcrack in the cermet with different hard phase content. The contiguity of the hard phase and the binder mean free path are discussed following the stereological principle. The relative density, hardness and transverse rupture strength of the cermet are measured with Archimedes principle, Rockwell hardness tester and three-point-bending method, respectively. With the increasing hard phase content, the average particle diameter of the hard phase firstly decreases and then increases. When the hard phase content is 75%, the cermet obtains the maximum relative density (98.4%), maximum hardness (HRA 89.2) and maximum transverse rupture strength (1 291 MPa). In the process of crack propagation, intergranular fracture and transgranular fracture simultaneously appear, but the former is in majority. Large Ti(C,N) grains are more prone to appear transgranular fracture. The stress concentration due to sharp corners of large particles leads to microcrack, which is not conducive to improve the mechanical properties of the material.