Grinding performance and delamination analysis of fesib metallic glass laminate

FeSiB metallic glass laminate is a state-of-the-art structure for improving the magnetic performance of magnetic core. Extreme strength and hardness due to the amorphous matrix challenge its grinding process with severe tool wear and pronounced delamination. An amount of heat generated during grinding process brings a considerable problem in material crystallization, resulting in an increased magnetic deterioration. In this work, grinding data is presented for grind wheel wear, cutting force and surface quality when routing 8 mm thick FeSiB metallic glass laminate using electroplated CBN grinding points. Grinding experiments were carried out with grinding speeds of 0.5 and 1.5 m/s to investigate the formation of delamination. Energy dispersive x-ray spectroscopy (EDS) and electron back scattered diffraction pattern (EBSD) analyses were conducted to inspect the delamination between the metallic foil layers and detailed microstructure of machined surface, respectively. The relation between the cutting force and delamination was discussed associated with the identification of crystallization condition of machined surface. As a result, plastic deformation between the layers is the primary reason for the inter-laminate circuit short. Load-displacement curve from nano indenter indicated the strain hardening level near machined surface increased with cutting speed.