The effect of molybdenum on the microstructure and mechanical behaviour of the sintered Fe-Mo-Mn-Si-C composite

Abstract

Abstract Experimental sintered Fe-Mo-Mn-Si-C composites were prepared from 3 different pre-alloyed Fe-Mo-Mn powders, namely Fe-0.50Mo-0.15Mn, Fe-0.85Mo-0.15Mn and Fe-1.50Mo-0.15Mn, mixed with fixed 4 wt.% silicon carbide powder. Sintered Fe-SiC composite was also prepared, as a reference material, from pure Fe powder mixed with fixed 4 wt.% silicon carbide powder. All specimens were processed by using the ‘press and sinter’ method. Sintering was performed in a vacuum furnace at 1250ºC for 45 minutes and slow cooling in the furnace. The microstructures of most sintered alloys showed a common feature consisting of a black particle enveloped with ferrite and pearlite. Sintered composites produced from high-molybdenum powders showed different matrices, in which some pearlite regions were replaced by BF/M- A structures. The Tensile and hardness test showed that the sintered alloys exhibited an increase of tensile strength, yield strength, and hardness with increasing molybdenum content. The pearlite + BF/M-A fractions of sintered composites played important roles in material strengthening. In the sintered composites produced from high-molybdenum powders, the carbide-free BF/M-A structure showed a promising strengthening effect.