High pressure induced the polymorphism phase transition in the Fe40Mn40Co10Cr10 multi-principal element alloy

Abstract

In this study, we systematically studied the high pressure polymorphism phase transition process in the Fe40Mn40Co10Cr10 multi-principal element alloy through the hexahedron pressure equipment and the high pressure synchrotron angle-dispersive x-ray diffraction technique. A mixture of face-center cubic (fcc) + hexagonal close packed (hcp) nanolaminate structure was observed for the samples after high pressure treatment at 5 GPa, through the hexahedron pressure equipment. Especially, the hcp lath interaction structure with a new secondary hcp phase at the intersection zone was discovered in the sample. Transmission Electron Microscopy (TEM) analysis revealed that the transition from fcc to hcp was accomplished by the glide of Shockley partial dislocations. In addition, the in-situ synchrotron angle-dispersive x-ray diffraction technique was carried out to detect the phase transition process of the Fe40Mn40Co10Cr10 alloy up to 40.4 GPa. The lattice constant, atomic volumes, bulk modulus, and volume fraction of the fcc and hcp phase were obtained during compression and decompression. These results can expand our understanding of the structure evolution and properties of multi-principal element alloys under extreme conditions such as high pressure, which is contribute to the development of new metastable structural materials.