In repair of aircraft structures of magnesium alloy ML10,the argon arc non-consumable electrode welding is used.In this case,the residual welding stresses occur in repairwelds,being one of the causes for reducing the ...In repair of aircraft structures of magnesium alloy ML10,the argon arc non-consumable electrode welding is used.In this case,the residual welding stresses occur in repairwelds,being one of the causes for reducing the service characteristics of the restored products.Residual stresses arise as a result of welding.Post-weld heat treatment is used to reduce the residual stresses.The heat treatment,which occurs after welding,increases the cost of repair.This leads to the search for alternative methods to control the stressed state of welded joints,one of which is electrodynamic treatment,which reduces the level of residual stresses in repair welds,and as a consequence,the cost of the welding repair in restoring aircraft structures.It was found from the results of experiments carried out,that the electrodynamic treatment allows reduces the initial level of stresses in welded joints,reaching 120 MPa,to 30 MPa,and at definite geometric characteristics of the specimens forming the field of compressive stresses,the values ofwhich are equal to-50 MPa.It is shown that the optimum distance between the zones of treatment,being 5 mm,provides the guaranteed covering the zones of electrodynamic effect and,as a consequence,the maximum efficiency of the electric dynamic treatment.展开更多
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 homogeneou...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.展开更多
文摘In repair of aircraft structures of magnesium alloy ML10,the argon arc non-consumable electrode welding is used.In this case,the residual welding stresses occur in repairwelds,being one of the causes for reducing the service characteristics of the restored products.Residual stresses arise as a result of welding.Post-weld heat treatment is used to reduce the residual stresses.The heat treatment,which occurs after welding,increases the cost of repair.This leads to the search for alternative methods to control the stressed state of welded joints,one of which is electrodynamic treatment,which reduces the level of residual stresses in repair welds,and as a consequence,the cost of the welding repair in restoring aircraft structures.It was found from the results of experiments carried out,that the electrodynamic treatment allows reduces the initial level of stresses in welded joints,reaching 120 MPa,to 30 MPa,and at definite geometric characteristics of the specimens forming the field of compressive stresses,the values ofwhich are equal to-50 MPa.It is shown that the optimum distance between the zones of treatment,being 5 mm,provides the guaranteed covering the zones of electrodynamic effect and,as a consequence,the maximum efficiency of the electric dynamic treatment.
文摘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.
