Magnetisms About Fully Amorphous And Partially Crystallized Amorphous Of Al-Ni-Y-Co-Fe Al-based Amorphous Alloys

Al-based amorphous alloys exhibit excellent performance with high specific strength (upto1000MPa) and good toughness. The strength is further improved when Al nano-crystals aredispersed within an amorphous matrix. However, the study of Al-based amorphous alloysmainly focuses on how to improve glass forming ability and how to make bulk Al-basedamorphous alloys. But, there are few reports and studies on magnetism of the amorphousalloys in the field of Al-based amorphous materials. Thus, studying the magnetism of theamorphous Al-based alloys is significant to promote the practical application and furtherdevelopment of the materials.This thesis mainly focuses on the magnetism of Al-Ni-Y-Co-Fe Al-based GFMs throughmelt spinning. Magnetic characteristics about completely amorphous and partially amorphousalloys for the as-quenched Al85Ni5Y4Fe2Co2alloys was tested by VSM (vibrating samplemagnetometer). The results showed that both magnetization curves of the amorphous alloyspassed through the origin of coordinates and through the first and the third quadrant, it canclearly saw that there was no remanence and coercivity in both two alloys. The results showedthat the magnetism of completely amorphous alloys and partially amorphous alloys was acomposite of paramagnetic and diamagnetic. Then we got the magnetic susceptibility afterfitting the linear portion of the curve, the completely amorphous alloy was2.41×10-4and thepartially amorphous alloy was2.73×10-4, so the partially amorphous alloy was easier to bemagnetized. Next, the magnetic characteristic about the amorphous alloys annealed at330℃and390℃were tested respectively. XRD showed that nano meter sized aluminum crystalswere found only in both annealing alloys before test, and the alloy annealed at330℃containsmore nanocrystals. The test showed that the magnetic susceptibility of the linear portion of thecurve increased from2.53×10-4to2.81×10-4as the annealing temperature rises from330℃to390℃.So we got that alloys after annealing in390℃is easier to be magnetized. It canconclusion that: Anti-magnetic structure appeared in the amorphous matrix, the more contentof anti-magnetic structure appeared when more crystals precipitate. The magnetic susceptibility become larger when lager number of the nano-aluminum crystal precipitated.