Microstructure and tensile strength of PM304 composite

PM304 composite comprising NiCr (80/20) matrix (60 wt.%) combined with Cr2O3 (20 wt.%), Ag (10 wt.%) and eutectic BaF2/CaF2 (10 wt.%) as solid self-lubricants additives has been successfully prepared by mechanical alloying and powder metallurgy. The sintered PM304 samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS). The density of PM304 composite sintered at 1100 °C was 7.3 g/cm3, and the mean tensile strength 47 MPa. The size of Cr2O3, BaF2/CaF2 particles was less than 1 μm, and that of Ag particles below 5 μm. Fracture morphology indicates that the fracture of PM304 is mainly along Ni80Cr20 grains.