The mechanical properties of the Al-7075 material, which is used in important areas such as automotive, aviation and defense industry, are still being studied by researchers. In this study, the effects of different proportions of Nb additives on the microstructure and mechanical properties of the rapidly solidified Al-7075 alloy was investigated. Rapid solidification processes were carried out with a single roller melt spinner at a disk surface speed of 25 m / s. Microstructure characterization was performed by using a scanning electron microscopy (SEM) and X-ray diffraction. According to the results, the Nb additive significantly increased the micro hardness of the Al-7075 alloy. The microhardness of the sample added with 0.5% by weight of Nb is 0.9 GPa. This value is 3 times higher than the sample without Nb added. The Nb contribution has led to modification of the dimensions and shapes of both α-Al and intermetallic phases. Nb addition reduced the average grain size from 9.1 µm to 2.46 µm.

Alloys of FeNiSiB soft magnetic materials containing variable Fe and Ni contents (wt.%) have been produced by melt spinning method, a kind of rapid solidification technique. The magnetic and structural properties of FeNiSiB alloys with soft magnetic properties were investigated by increasing the Fe ratio. X-ray diffraction analysis and SEM images shows that the produced alloy ribbons generally have an amorphous structure, together with also partially nanocrystalline regions. It was observed that the structure became much more amorphous together with increasing Fe content in the composition. Among the alloy ribbons, the highest saturation magnetization was obtained as 0.6 emu/g in the specimen with 50 wt.% Fe. In addition, the highest Curie temperature was observed in the sample containing 46 wt.% Fe.

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Within the scope of the study, NdFeB-based permanent magnet alloys produced by melt spinning method, which is a kind of rapid solidification method and enables the production of amorphous and/or semi-crystalline alloys in the form of strips, were produced. In addition, the effect of flash annealing heat treatment on magnetic properties at 680 and 710 °C for 10 minutes using very fast heating and cooling rates of 290 K/s was investigated. A new alloy was obtained by adding 30% by weight of waste magnet to the NdFeB based permanent magnet alloy used in our study. In addition to the effect of heat treatment, another aim of our study is to reuse waste magnets and to recover rare earth elements from waste magnets. Along with the increasing heat treatment temperature, a decrease was observed in magnetic coercivity from 16546 Oe to 2349 Oe, maximum energy product from 136 kJ/m3 to 10 kJ/m3, and magnetic remenance from 56 emu/g to 22 emu/g, which reveals permanent magnetism. On the other hand, there was no significant change in saturation magnetization, but a slight increase was observed from 93 emu/g to 90 emu/g.

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