Effect of milling time on the microstructure and mechanical properties of Ti(C,N)-304 stainless steel cermet

Effect of milling time on the microstructure and mechanical properties of Ti(C,N)-304 stainless steel cermet and the fracture mechanism were studied in this work. The microstructure was investigated by means of x-ray diffraction (XRD), scanning electron microscope (SEM) combined with energy dispersive spectrometer (EDS), and field emission transmission electron microscope (FETEM). FETEM and EDS were also used to analyze the Ti(C,N)/304ss interface. Mechanical properties such as transverse rupture strength (TRS) and hardness were also measured. Results show that prolonged milling time decreases the Ti(C,N) grain size and improves the homogeneity of microstructure. As a consequence, the frequency of intergranular fracture increased and it can improve the mechanical properties. Fe and Ti elements could interdiffuse and the hard phase was closely bonded with binder phase. The Ti(C,N)/Ti(C,N) interface was weaker than Ti(C,N)/304ss interface. Results also show that the transverse rupture strength and the hardness increase with increasing milling time and the maximum values were obtained at 18 h with 1437 MPa and 83.7 HRA, respectively.