Study On The Crystallization And Corrosion Behaviors Of Al-RE-TM Based Amorphous Alloys

Amorphous alloy has long-range disorder, special structure of the short-range order, not like crystal material has defects such as dislocations, grain boundaries and dislocations. Al-based amorphous alloys containing Al over85at.%possess the characteristics of high strength, low density, especially Al-RE-TM (RE for rare earth elements, TM for transition metal elements) system due to the excellent mechanical properties, electromagnetic properties and corrosion resistance, is worth further study. Amorphous alloy has long-range disorder, special structure of the short-range order, not like crystal material has defects such as dislocations, grain boundaries and dislocations.In this dissertation, the amorphous ribbons of Al-Ce-TM systems were prepared by melt-spinning (MS) method. Using X-ray diffractometer (XRD) was carried out on the Al-Ce-TM phase analysis, differential scanning thermal analysis (DSC) was used to Al-Ce-TM crystallization process were analyzed, and according to the measured DSC curve to determine the vacuum heat treatment temperature, under the environmental protection of argon gas, the amorphous Al-Ce-TM annealing treatment.Under different temperature of heat treatment of Al-Ce-TM, the XRD analysis, calibration precipitated phase.At the same time, in3.5wt.%NaCl solution, pH value of2HCl solution was carried out on the experimental sample electrochemical analysis and SEM analysis.It is concluded that (1) of the amorphous alloy Al88Ce8Fe4glass transition temperature Tg at300℃, the first step crystallization start Tx1temperature is300℃, the second step crystallization start Tx2temperature is364℃, with the increase of temperature, precipitation for fcc-Al phase, Al4Ce phase, Al11Ce3phase, AlFe3phase.Annealing temperature is304℃of the alloy in3.5wt.%NaCl solution, the corrosion performance of HCl solution with a pH2best.(2) the glass transition temperature of the amorphous alloy Al88Ce8Co4Tg at282℃, the first step crystallization start Tx1temperature is282℃, the second step crystallization Tx2start temperature of313℃, with the increase of temperature, precipitation for fcc-Al phase, Al11Ce3, Al4Ce and AlCo phase.Annealing temperature is284℃at3.5wt.%NaCl solution, the corrosion performance of HCl solution with a pH2is best.(3) of the amorphous alloy Al88Ce8Ni4glass transition temperature Tg at242℃, the first step crystallization start Tx1temperature is248℃, the second step crystallization Tx2start temperature of334℃, with the increase of temperature, precipitation for fcc-Al phase, AlCeNi phase, Al4Ce phase, AlCe phase.Annealing temperature is250℃at3.5wt.%NaCl solution, the corrosion performance of HCl solution with a pH2is best.(4) of the amorphous alloy Al88Ce8Cu4glass transition temperature Tg at215℃, the first step crystallization start Tx1temperature is215℃, the second step crystallization Tx2start temperature of288℃, with the increase of temperature, precipitation for fcc-Al phase, Al4Ce phase, Al92Ce8phase, CeCu2phase.Annealing temperature is219℃at3.5wt.%NaCl solution, the corrosion performance of HCl solution with a pH2is best.