Different sintered alloys were produced by sintering and slow cooling of powder compacts made from pre-alloyed Fe-0.50Mo-0.15Mn powder mixed with varied graphite powder contents (0.30-1.20 wt.% with 0.15% increment). According to microstructures, sintered alloys were divided into sintered hypo-eutectoid, near eutectoid, and hyper-eutectoid alloys. By using Groesbeck color tinting and X-ray diffraction technique, the common phase transformation products of these sintered alloys were found to include ferrite and carbides. The sintered hypo-eutectoid alloys had microstructures consisting of polygonal ferrite grains and two forms of ferrite + carbide mixtures, such as ferrite + M 23 C 6 carbide and ferrite + M 3 C carbide. In sintered near-eutectoid alloys, only ferrite + M 3 C carbide mixtures occupied microstructures. In sintered hyper-eutectoid alloys, large proeutectoid M 23 C 6 carbide formed first and followed by abnormal ferrite, degenerate ferrite + M 23 C 6 pearlite, lamellar ferrite + M 23 C 6 pearlite, Widmanstätten M 3 C carbide, inverse bainite (ferrite + M 3 C) and upper bainite (ferrite + M 3 C).
Sintered Fe-Mo-Mn-C alloys were produced by sintering of mixtures of pre-alloyed Fe-0.5Mo-0.15Mn powder and varied carbon amounts (0.30-1.20 wt.% with 0.15% increments) followed by slow cooling in furnace. Microstructures and mechanical properties of the sintered alloys varied with added carbon content. With up to 0.75 wt.% carbon additions, the sintered alloys exhibited polygonal ferrite plus non-cooperative eutectoid decomposition products. With 0.90 wt.% carbon addition, the whole microstructure of the sintered alloy mainly consisted of non-cooperative eutectoid decomposition products. With 1.05 and 1.20 wt.% carbon additions, the microstructures of the sintered alloys consisted of large grain boundary carbides and mixed non-cooperative and cooperative eutectoid decomposition products within grains. Tensile strength showed the maximum value in the sintered alloy with 1.05 wt.% carbon addition. Elongation values decreased sharply with increasing carbon contents of up to 0.60 wt.%, beyond which the values were constant.
Sintered Fe-1.50Mo-xC alloys were produced by the sintering of powder compacts made from mixtures of pre-alloyed Fe-1.5Mo powder and varied carbon amounts (0.30-1.20 wt.% with 0.15 increment) followed by slow and fast cooling rates. The slowly cooled sintered Fe-1.50Mo-xC alloys (for carbon contents of up to 0.45 wt.%) showed microstructures consisting of polygonal ferrite grains and eutectoid transformation products. When carbon contents were higher than 0.45 wt.%, eutectoid transformation products were dominant. The fast-cooled sintered Fe-1.50Mo-xC alloys (for carbon contents of up to 0.75 wt.%) showed microstructures consisting of upper bainite. When carbon contents were higher than 0.75 wt.%, upper bainite and inverse bainite were dominant. Tensile strength and hardness values of sintered Fe-1.50Mo-xC alloys increased with increasing carbon content. In addition, fast cooling further enhanced mechanical properties of the sintered alloys. It was found that values of ultimate tensile strength (UTM) and hardness on slow and fast cooling rates were 385-565 MPa, 564-743 MPa, 43-78 HRB and 60-82 HRB, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.