MICROSTRUCTURAL CHANGES IN MAGNESIUM ALLOY Mg-Zn-REE AFTER IRRADIATION WITH NANOSECOND LASER PULSES

The article presents the results of studies of the structure and composition of the surface and near-surface layers of the Mg-Y-Zn-Nd-Yb-Zr alloy system with a long-period phase after irradiation with nanosecond laser pulses using electron microscopy and energy-dispersive X-ray microanalysis. It is shown that in a two-phase alloy, a layer of nanocrystalline MgO with a thickness from 5 nm to hundreds of nm is formed on the surface in the α-Mg matrix region. A recrystallized layer of columnar crystallites with a thickness of about 1 μm and a lateral size of 0.2-1 μm with inclusions of cubic MgO is formed under it. In the area of the intermetallic compound (phase MgYZn-REE type 18R), a three-layer amorphous-crystalline structure is formed: an amorphous layer 15-20 nm thick on the surface, under it a crystalline layer of columnar crystallites 0.1-0.3 μm thick and with lateral dimensions of 0.1-0.5 μm, then an amorphous layer of intermetallic compound about 1 μm thick.