Research On MA And SPS Technologies For Preparation Of Fe-based Amorphous Alloys

As a kind of novel functional material, not only amorphous alloy themselves havevarious excellent properties, but also as a kind of matrix, they can be made into nanomaterials or composite materials of nanocrystal and amorphous, and some of theirproperties will get more breakthroughs. As they are limited by the preparationtechnologies and processes, the three-dimensional size of amorphous alloys material isdifficult to meet the size requirements in practical applications, which makes the superiorperformance of amorphous alloy materials limited in practical application. So the researchon the process of preparation of big bulk amorphous is imperative.Compared with conventional liquid quenching technique, mechanical alloying （MA）technique can prepare amorphous alloys of which the composition is difficult to formamorphous alloy by liquid quenching technique. Spark plasma sintering （SPS） technology,which has the features of fast heating rate and short sintering time, is more suitable forsintering bulk amorphous alloys materials than the traditional sintering processes. Thisdissertation focuses on the preparation of Fe-based amorphous alloys materials and thenew powder metallurgy technologies of mechanical alloying technique and spark plasmasintering technology, which are used to prepare Fe-based amorphous alloys, arethoroughly investigated.At first, two kind of Fe-based amorphous alloys powder of Fe₅₀Ni₃₀B₁₀C₁₀andFe60Fe₆₀Ni₂₀B₁₀C₁₀components were prepared by mechanical alloying technique. X-raydiffraction （XRD） and scanning electron microscope （SEM） were used to analyze theinfluence of the element content and critical milling process parameters on theorganization and structure of the powders. Differential scanning calorimeter （DSC） wasused to analyze the thermodynamic properties, thermal stability, characteristics oforganizational changes and dynamic characteristics of the crystallization of Fe-basedamorphous alloy powder. Vibrating sample magnetometer （VSM） was used to analyze themagnetic of the powders.Secondly, the amorphous powder of Fe₅₀Ni₃₀B₁₀C₁₀component was made into bulk amorphous alloy samples by spark plasma sintering technology, and the bulk amorphousalloy samples of 20mm in diameter and 10mm in thickness were got under conditions ofsintering pressure 500Mpa and heating rates of 40 degrees per minute. The influence ofcritical parameters of spark plasma sintering technology,such as sintering temperature,sintering pressure and velocity of sintering on the organization, structure and density ofbulk amorphous alloy samples were analyzed.At last, vibrating sample magnetometer was used to research the magnetic propertiesof the bulk Fe-based amorphous alloys by sintering, and the influence of the organizationof the bulk samples and sintering process parameters, which included sinteringtemperatures and sintering pressures, on the magnetic properties of bulk amorphous alloyssamples by sintering, such as saturation magnetization, coercivity, permeability and theremanent magnetization and so on were analyzed.