Influence Of Carbon, Copper, Nickel On Properties Of Iron Based P/M Material

The effect is discussed of carbon, copper, nickel, content on flow rate, mechanical properties, metallurgical structure and breakpoint microstructure of iron based P/M materials. All the study base on atomized iron powder ATOMET 4401 which made by Quebec Metal Powders Ltd.(QMP) Canada.It said in this paper, the flow rate of base powder become worse with adding of graphite, copper or nickel. Graphite can make the dimensional change of PM applications goes toward extension direction, especially when graphite in range of 0~0.8 wt %. Copper can make the dimensional change of PM applications goes toward extension direction when base powder with low carbon content, and the DC(dimensional change) increase more positive with higher copper content. It's different with high carbon content, the DC of PM application will not increase significant with more copper adding, the DC can even goes slightly negative when carbon content high as 0.9 wt %. Nickel can make the DC of PM applications goes towards contraction direction; the DC goes from positive to negative when nickel content around 1 wt %; and the DC contract more obviously with more higher nickel content.It's same direction of affect on hardness of PM applications with adding copper and nickel. The hardness can get enhanced with adding copper or nickel.When carbon content of PM applications in range of 0.3 wt %~0.6 wt %, TRS (transverse rupture strength) and TS (tensile strength) can get enhanced with copper adding, more better TRS and TS can be achieved at 0.6 wt % carbon content. TRS and TS increased rapidly with nickel adding at 0.3 wt % carbon content; TRS and TS increased slowly with nickel adding at 0.6 wt % carbon content; TRS and TS nearly no change with nickel adding at 0.9 wt % carbon content. The analysis from elongation showed that carbon and copper affect the plastic deformation of PM application on negative direction, meanwhile nickel is a kind of good additive to increase the plastic deformation.It is indicated from the analysis of metallurgical structure of sinterined iron based P/M materials, that we will get the same metallurgical structure (in the same sintering condition) with adding different kinds of additives of carbon, copper and nickel. And the metallurgical structure we get is martensite.The ail holes and low-melting phase are increased with adding carbon and copper, so the plasticity of sintered iron based P/M materials is negatively impacted. On the contrary, the plasticity improved with adding nickel. It could be caused by that the air holes become small and less, the connectivity of low-melting phase become weak.It's indicated from the analysis of fracture morphologies, that the plastical deformation around the breakpoits obviously better with composition of Fe-0.9C-4N rather than Fe-0.3C-4Ni if we keep the same percentage of nickel in the composition.