A new severe plastic deformation method for manufacturing tubes made of AZ31 magnesium alloy with a large diameter was developed,which is called the TCESE(tube continuous extrusion−shear−expanding)process.The process ...A new severe plastic deformation method for manufacturing tubes made of AZ31 magnesium alloy with a large diameter was developed,which is called the TCESE(tube continuous extrusion−shear−expanding)process.The process combines direct extrusion with a two-step shear−expanding process.The influences of expanding ratios,extrusion temperatures on the deformation of finite element meshes,strain evolution and flow velocity of tube blanks during the TCESE process were researched based on numerical simulations by using DEFORM-3D software.Simulation results show that the maximum expanding ratio is 3.0 in the TCESE process.The deformation of finite element meshes of tube blanks is inhomogeneous in the shear−expanding zone,and the equivalent strains increase significantly during the TCESE process of the AZ31 magnesium alloy.A extrusion temperature of 380°C and expanding ratio of 2.0 were selected as the optimized process parameters from the numerical simulation results.The average grain size of tubes fabricated by the TCESE process is approximately 10μm.The TCESE process can refine grains of magnesium alloy tubes with the occurrence of dynamic recrystallization.The(0001)basal texture intensities of the magnesium alloy tube blanks decrease due to continuous plastic deformation during the TCESE process.The average hardness of the extruded tubes is approximately HV 75,which is obviously improved.展开更多
The consolidation recycled AZ80 billets were successfully fabricated through the cold press and hot press sintering of the AZ80 metal chips.The consolidation recycled billets sintered at 350℃present the comparable co...The consolidation recycled AZ80 billets were successfully fabricated through the cold press and hot press sintering of the AZ80 metal chips.The consolidation recycled billets sintered at 350℃present the comparable compressive properties and inferior tensile properties compared with the initial cast billets.The defects in the consolidation recycled billet were inclined to propagate along the bond interface between the metal chips during tension,which resulted in the inferior tensile properties of the recycled billets.The recycled billets were then subjected to the integrated extrusion-shear(ES) process.The homogeneous finer dynamic recrystallization grains with an average grain size of 6 μm can be obtained in the shear deformation zone and extrusion sizing zone through integrated ES process at 300℃with an extrusion velocity of 0.6 mm/s.The recycled billets after integrated ES forming process present rival tensile properties compared with the initial cast billets after integrated ES forming with the same extrusion parameters,which can be ascribed to that the integrated ES forming can nearly eliminate the defects through the severe compressive and shear strain.The solid-state recycling process through hot press sintering and subsequent integrated ES process can fabricate the consolidation recycled AZ80 rod,which demonstrates the comparable tensile properties with the cast-extrusion rod.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.52071042,51771038)the Chongqing Talent Plan,China (No.CQYC202003047)Chongqing Natural Science Foundation,China (Nos.cstc2018jcyj AX0249,cstc2018jcyj AX0653)。
文摘A new severe plastic deformation method for manufacturing tubes made of AZ31 magnesium alloy with a large diameter was developed,which is called the TCESE(tube continuous extrusion−shear−expanding)process.The process combines direct extrusion with a two-step shear−expanding process.The influences of expanding ratios,extrusion temperatures on the deformation of finite element meshes,strain evolution and flow velocity of tube blanks during the TCESE process were researched based on numerical simulations by using DEFORM-3D software.Simulation results show that the maximum expanding ratio is 3.0 in the TCESE process.The deformation of finite element meshes of tube blanks is inhomogeneous in the shear−expanding zone,and the equivalent strains increase significantly during the TCESE process of the AZ31 magnesium alloy.A extrusion temperature of 380°C and expanding ratio of 2.0 were selected as the optimized process parameters from the numerical simulation results.The average grain size of tubes fabricated by the TCESE process is approximately 10μm.The TCESE process can refine grains of magnesium alloy tubes with the occurrence of dynamic recrystallization.The(0001)basal texture intensities of the magnesium alloy tube blanks decrease due to continuous plastic deformation during the TCESE process.The average hardness of the extruded tubes is approximately HV 75,which is obviously improved.
基金financially supported by the National Natural Science Foundation of China (No. 51875127).
文摘The consolidation recycled AZ80 billets were successfully fabricated through the cold press and hot press sintering of the AZ80 metal chips.The consolidation recycled billets sintered at 350℃present the comparable compressive properties and inferior tensile properties compared with the initial cast billets.The defects in the consolidation recycled billet were inclined to propagate along the bond interface between the metal chips during tension,which resulted in the inferior tensile properties of the recycled billets.The recycled billets were then subjected to the integrated extrusion-shear(ES) process.The homogeneous finer dynamic recrystallization grains with an average grain size of 6 μm can be obtained in the shear deformation zone and extrusion sizing zone through integrated ES process at 300℃with an extrusion velocity of 0.6 mm/s.The recycled billets after integrated ES forming process present rival tensile properties compared with the initial cast billets after integrated ES forming with the same extrusion parameters,which can be ascribed to that the integrated ES forming can nearly eliminate the defects through the severe compressive and shear strain.The solid-state recycling process through hot press sintering and subsequent integrated ES process can fabricate the consolidation recycled AZ80 rod,which demonstrates the comparable tensile properties with the cast-extrusion rod.
