Microstructure and properties of the Nd2Fe14Bp/Al-Co composites fabricated via microwave sintering

This study aimed to fabricate a new type of aluminum matrix composite exhibiting high strength, good magnetic property, and toughness to solve the issues on current magnetic materials, such as brittleness and high density. In this paper, the Nd2Fe14Bp/Al-Co composites with different cobalt (Co) contents (wt.%) are fabricated via microwave sintering. The effects of the Co content on the composite microstructures and properties are studied. The results indicate that at a 580 degrees C sintering temperature, 30 min sintering time, and 30 degrees C/min heating rate, with an increase in the Co content (0 -> 1%-> 2.5%-> 5%-> 7.5%-> 10%), the compactness initially increases and then decreases and reaches the maximum of 94.5% for the 5%Co sample together with a smaller grain size. The composites mainly consist of Nd2Fe14B with various sizes, Co particles, and the Nd-2(Fe,Co)(14)B phase. The interfacial deformation resistance of the 5%Co sample tested via nanoindention is 22.8% higher than that of the Co-free sample, which can facilitate in the interfacial strengthening. The microhardness, yield strength, and tensile strength of the 5%Co samples are 107.4 HV, 210.84 MPa, and 139.8 MPa, respectively. The remanence B-r, coercive force H-cj, and maximum magnetic energy product (BH)(max) of the 5%Co sample are 0.37 T, 0.65 T, and 45.12 kJ/m(3), respectively, which are 48.6%, 29.2%, and 63.9% higher than those of the Co-free sample. The significant increase in the magnetic properties is mainly attributed to the interactive coupling between the Co particle soft magnetic phase and Nd2Fe14B hard magnetic phase. (C) 2020 The Author(s). Published by Elsevier B.V.

Automated summary

This study successfully fabricated a new type of aluminum matrix composite with high magnetic properties and toughness, and investigated the effects of different cobalt contents on the material properties. The results showed that increasing the cobalt content can enhance the compactness and magnetic properties of the composite material, as well as facilitate interfacial strengthening.