On Process And Microstructure Of Fe-Al And Fe-Si-Al Alloy Prepared By Mechanical Alloying

Fe based nanocrystalline is a kind of attractive functional material, owing to excellent soft magnetic properties. Mechanical alloying (MA) is expected to produce Fe based nanocrystalline with high performance. The mechanical alloying process and microstructure of Fe-6.5wt%Si alloy powder,Fe-Al alloy powder and FeSiAl alloy powder are studied in this paper.The phases, microstructures, morphologies, cross-sections of mechanical alloying powders were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy spectrometer (EDS) analysisrespectively. The main results are as follows:Prolonging milling time, increasing CR and decreasing initial particle size can improve producing Fe-wt6.5%Si alloy powder efficiency. Fe-Si alloy has a stable composition, uperstaturated solid solution with the sub-micron structure, during vibrate ball milling in argon. he optimum method in this paper is milling time for 12h,CR for 10/1 and original partical size for～1mm.Nanocrystallineα-Fe (Al) solid solution has created after Fe_(100-x)Al_x(x=4,8,12wt%)mixture powder ball milling for 20h, with the structure of b.c.c , particle size from 1μm to 30μm and nanocrystalline sub-micron structure . Two kinds of Fe-Al powders are obtained in the process, one is a composite powder with a typical laminar structure, and the other is a powder with iron as the inner core.With the more time of ball milling, alloy partical size and grain size becames smaller and smaller and two kind elements of Fe and Al distribute well-proportioned gradually.After ball milling for 30h the distortion of lattice is up to 0.54%. No amorphous phase forms during the mechanical alloying process.Under condition of this paper the more content of Al, the more felt is.Nanocrystallineα-Fe (Si,Al) solid solution has created after(FeSi)_(100-x)Al_x(x=15,20, 25at%) mixture powder ball milling for 10h, with the structure of b.c.c , particle size from 1μm to 20μm and nanocrystalline sub-micron structure . After ball milling for 15h grain size is up to 30nm. Mixture powder is a composite powder with a typical laminar structure.With the more time of ball milling, alloy partical size and grain size became smaller and smaller , every element distribute well-proportioned gradually and the surface of particle becomes smooth ,the shape of particle becomes spheric shape. No amorphous phase forms during the mechanical alloying process.