The Impact Of Supercooling Degree On Iron And Copper Alloys And The Research On Iron And Copper Alloys Cutting Machinability

Fe-20%Cu alloy is a new kind of motor rotor material. It is at low cost andeasy to melt. Fe-20%Cu alloy has good comprehensive mechanical propertiesand magnetic conductivity. So it attracts people’s attention gradually. Going intoFe-20%Cu alloy is very important for the development of iron and copper alloy.In this paper, thermodynamic analysis for the Fe-20%Cu alloy equilibriumprecipitates is carried out. What’s more, the Fe-20%Cu alloy in the binary systemof Fe and Cu in the Gibbs free energy is calculated. I conducted the castmicrostructure analysis of Fe-20%Cu alloy, X-ray diffraction analysis, micro-composition analysis, mechanical properties testing at room temperature. I alsostudied the influence of different cooling rate on the microstructure andproperties of Fe-20%Cu alloy. The cast and the normalized Fe-20%Cu alloycutting experiments are conducted to study the cutting performance. Theexperimental results show that:Thermodynamic calculation indicated that, in the Fe-20%Cu alloysolidification process, when the temperature decreases to1815K, γ-Feprecipitates from the liquid phase first. As the temperature continues to drop to1431K, ε-Cu starts to precipitate from the liquid phase.Dynamic analysis shows that, with undercooling ΔT decreasing, thedistribution of copper in the Fe-20%Cu alloy, the morphology changed fromcontinuous net to intermittent mesh and then columnar or isolated island. In thisprocess, intermittent linear structure gradually reduce which contains more Fe.With the decrease of the supercooling degree ΔT, Cu precipitates at grain boundary preferentially. The number of the precipitation in the intracrystallinedecreases.Mechanics performance test show that with the degree of supercooling ΔTdecreases, the hardness value of samples is lower. The hardness of metal typespecimen is highest, resin sand mold sample secondly, refractory brick lowest.The cutting experiments show that the cutting performance of Fe-20%Cualloy can meet the general requirements of machining. By comparing the cuttingforce of two kinds of materials in different heat treatment process, the cuttingforce required of the iron copper alloy after normalizing is greater than that ofthe cast Fe-20%Cu alloy. Surface roughness is higher than the cast Fe-20%Cualloy, too. The cutting properties of the alloy is improved.