The dynamic mechanical properties of NdFeB ferromagnet under shock wave compression

In order to investigate the dynamic mechanical properties of NdFeB ferromagnet, the planar impact experiments are conducted by gas gun planar impact technique. The manganinpressure gauge is used to measure the pressure changes in NdFeB ferromagnet. The shock Hugoniot relation and the Grüneisen equation of state for NdFeB are obtained based on the analysis of the experimental data. The shock Hugoniot relation is described by the linear relation in the pressure range from 3.3 GPa to 7.2 GPa, by which the parameters in the Grüneisen equation of state are determined. The shock pressure region is enough to make the magnet to be completely demagnetized according to the hysteresis loops. A two-dimension simulation model is established according to the planar impact experiment, and the numerical simulation is performed by the nonlinear dynamics method. In order to analyze the mechanism of shock demagnetization, the microstructure, crystal structure, and magnetic properties of the magnets are examined with scanning electronic microscope, X-ray diffractor, hysteresis loop measurement instrument, and vibrating sample magnetometer, respectively.