ANOTHER LOOK AT THE EFFECT OF Cu ON THE MECHANICAL PROPERTIES OF AS- SINTERED Fe-Cu-C ALLOYS

摘要

Fe - Cu - C alloys with different Cu additions varying from 1.0% to 3.50%, in incremental steps of 0.50% and constant graphite content of 0.75% were prepared. Rectangular bars were pressed at a density of 7.10 cm~3 and sintered at a temperature of 1120°C for 20 minutes in an atmosphere consisting of 90% Nitrogen and 10% Hydrogen. In addition, bars prepared with the mix with 2.50% Cu were compacted at a density of 6.90 g/cm~3 and sintered in the same furnace under the same conditions as mentioned above. Cylindrical specimens were machined from the bars and submitted to tensile testing. An almost perfectly linear trend of strength and hardness versus Cu content was obtained up to 2.50% Cu. Axial and rotating bending fatigue testing was conducted on cylindrical specimens machined from the bars compacted at 6.90 g/cm~3. In addition, an automotive component, manufactured with the alloy with 2.50% Cu was submitted to fatigue testing under two surface conditions: as-sintered and shot peened. Results showed improvements in the fatigue strength of the shot peened component and a change in its failure location.