3d-visualization of magnesium strengthening mechanisms for a description of experimentally obtained data of alloying effect in Mg-Ga system

Based on laws of theory of materials strengthening were discribed the experimentally obtained alloying effect in Mg-Ga system and shown using program for 3d atomic structures. As known from our experiments a homogeneous wavy microstructure of the diffusion zone forms as result of mass-transfer of molten gallium into the volume of magnesium alloys. SEM chemical composition shows Mg 65% wt. and Ga 35% wt. and X-ray spectra diffraction data - Mg5Ga2 intermetallic phase formation. Such intermetallic diffusion zone provides the significant strengthening effect of microstructure which was determined experimentally by the indentation method. The 3-d visualization shows the reaction and changing of an original crystal structure of magnesium atomic lattice upon diffusion doping with foreign atoms of gallium and then is shown the coalescence of Mg5Ga2 intermetallic crystal with crystals surfaces of Mg-matrix. So, investigated Mg-alloy strengthening at alloying with Ga explained by two main factors. At first is the formation of intermetallic phases with the ordering and consolidation of the crystal structure of the matrix by the ligature atoms, which is the key factor of the strengthening mechanism fixed experimentally. Second, when hexagonal and orthorhombic atomic structures growth according to their spatial type, a significant disorientation of structural fragments occurs, an increase in the density of the amorphous transition layer, a twinning of the structure in the interphase boundaries, which leads to the formation of intrinsic mutual deformation and a high level of internal stresses. (C) 2020 Published by Elsevier B.V. on behalf of Chongqing University.