| It attracted widespread concern of many researchers on Fe-based amorphous alloy because of high strength, outstanding corrosion resistance and excellent soft magnetic properties, especially iron rich resources and low preparation cost. Fe41Co7Cr15Mo14C15B6Y2 amorphous alloy is the biggest Fe-based bulk metallic glasses so far. HITPERM-type alloys are a kind of materials with excellent soft magnetic properties.In this paper, Fe-based bulk metallic glasses and amorphous alloys with different components were prepared by mold-casting process and the single-roller-quenching method respectively. Moreover, they were studied about microstructure and properties.It was chose as experimental samples that Fe-based bulk metallic glasses with 5 mm and 3 mm in diameter and HITPERM-type amorphous alloy strip. The amorphous structure was confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Mossbauer spectra (MS), etc. The properties of the bulk metallic glasses and amorphous strip were investigated by differential thermal analysis (DTA), electrochemical measurement technology, friction and wear test, hardness test and magnetic test. Furthermore, the surface morphology of the samples were observed by scanning electron microscopy (SEM). The main research results were summarized as follows:(1) We prepared Fe41Co7Cr15Mo14C15B6Y2 bulk metallic glasses with 5 mm and 3 mm in diameter by copper mold-casting method and Fe(Co)-M-B-Cu (M=Nb、Zr、 Hf, etc.) amorphous strip by single-roller-quenching method. Then, the results of the XRD and TEM show the samples are amorphous structure.(2) The corrosion resistance and friction and wear characteristics of bulk metallic glasses were studied by electrochemical measurement and friction and wear test. The results show that the Fe41Co7Cr15Mo14C15B6Y2 bulk metallic glasses have good corrosion resistance in different four solutions, such as 1 mol/L HCl,1 mol/L HNO3,1 mol/L NaOH and 3.5% NaCl. Compared the results, it indicated that the best corrosion resistance in salt solution, intermediate in acid solution and worst in alkaline solution. For the same kind of solution, the corrosion resistance of the amorphous alloy decreases with the concentration increasing. Compared the corrosion resistance of the bulk metallic glasses and stainless steel, it was found that the corrosion resistance of amorphous alloys is better than stainless steel in salt and acid solutions, but worse than stainless steel in alkaline solution.(3) The results of friction and wear test exhibited better wear resistance at room temperature. There is a critical value on influence of load for the friction and wear. Compared the two materials, it was found that the wear resistance of the amorphous alloys is equivalent to that of stainless steel. The results of hardness test indicated that the hardness value close to centre is higher than that of close to edge at the same load.(4) We studied the effects about the thermal stability analysis of amorphous strip, such as linear speed of copper wheel、the adding way of B、the number of master alloy smelting and components of alloys through the discussion of thermodynamics by means of DTA curves and calculation of the crystallization activation energy. The results indicated that it has better thermal stability of amorphous strip when it has big speed or pure B, or less number of master alloy smelting. Thermal stability of strip samples is good when it has moderate content of Co or Zr instead of Hf. Moreover, it can increase the thermal stability when it has no Cu in amorphous alloys.(5) Fe-based amorphous alloys were treated by medium frequency pulse magnetic field in order to optimize the properties. Then it was characterized by XRD, TEM and MS. The results indicated that amorphous strip were nanocrystallized after treated by pulse magnetic field. There are nanocrystal phase dispersed in the amorphous matrix. It formed the amorphous-nanocrystal double phase alloys. Moreover, it can change the the magnetostrictive coefficient of the amorphous alloys. |
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