Microstructure and Magnetic Properties of NdFeB Based Nanocomposites to Shock Compression

摘要

Three typical Nd-Fe-B permanent magnetic alloys of Nd_(13)Fe_(75)B_6Al_6, Nd_(13)Fe_(79)B_6Si_2 and Nd_(13)Fe_(80)B_6Zr_1 have been presented to study the effect of annealing and shock compression on the microstructure, magnetic and mechanical properties. The response of NdFeB based nanocomposites mixed with medium particle morphologies of Al, Si and Zr, respectively were conducted under high shock pressure. The starting materials were prepared by rapidly quenching and melt-spinning of NdFeB based powders under vacuum at different temperatures. The magnetic properties on Br, Hci and (BH)_(max) tend to increase with rising annealing temperature, and reach their highest value at either 700□ or 750℃. The addition of Zr and Si enhance the chemical short range reaction and stablize the residual amorphous matrix. For recovery shock-consolidate compression, Br and Hci reach to a peak value at about 5.5 GPa which can be closely associated with the retention of nanostructure and strong exchange coupling between hard and soft magnetic phases. Secondly, the main work is to experimentally investigate the mechanics of the deformation processes leading to shock-induced chemical reaction. The results showed that the fracture mechanism on three specific magnetic alloys reveal that the Nd_(13)Fe_(79)B_6Si_2 sample, and the addition of Zr in NdFeB will lead to embrittlement of the ductile morphology.