Effects of high pressure on microstructure and properties of bulk (PrNd)xAl0.6Nb0.5Cu0.15B1.05Fe97.7-x alloys

According to nominal composition (PrNd)xAl0.6Nb0.5Cu0.15B1.05Fe97.7-x(weight percentage), the sintered NdFeB magnets are prepared by melting processing, milling processing, moulding processing and sintering processing. Microstructures and properties of these bulk samples at different high pressures are tested. It is shown that with pressure increasing, appearance and microstructure of samples are destroyed, but their inoxidizability at high temperature is increased, although their flexure strength is badly reduced. On the other hand, there are more excellent magnetic properties of bulk NdFeB samples pressed at high pressures (1.5 GPa and 3.0 GPa) than those of this bulk samples without being pressed. For example, values of their maximum magnetic energy products are increased by 7.69 kJ·m-3 and 0.94 kJ·m-3 respectively, and values of their remanence are increased by 0.02 T and 0.01 T respectively, in addition, the values of their intrinsic coercive force are increased by 20.06 kA·m-1 and 30.33 kA·m-1 respectively. It is ind that high pressure has some effects on microstructure, mechanical and magnetic property of the bulk NdFeB alloy.