STRUCTURES, PROPERTIES AND FRACTURES OF Fe-P-C-Cu-Mo SINTERED ALLOYS

This paper deals with the structures, properties and fracture modes of Fe-P-C-Cu-Mo sintered alloy. The effects of alloy elements and sintering temperature on structures and properties and the influences of phosphorus distribution on fracture modes at different tempering temperature have been studied.
Experimental results showed that good properties of Fe-0.60%P-0.44.%-1.0% Cu-0.50%Mo sintered alloy can be obtained after sintering at the temperature range of 1160-1240℃ for 1-2 hours.Its combined mechanical properties can be obviousiy improved after futher quenching from 850-900℃ and then tempering at 200℃ or 600℃. It was found in present experiments that when alloy was tempered at 200℃, molybdenum dissolved in matrix inhibited the grain boundary segregation of phosphous,and made the fracture modes of alloy become cleavage facture. Tempering at 400℃ causes intergranular fracture because during tempering at 400℃ molybdenum form molybdenum carbide, phosphorus mainly segregates into grain boundaries After tempering at 600℃, phosphorus segragates on the pore surfaces and fracture modes became ductile dimpled fractures.