The difference in the microstructure,texture in the stir zone(SZ)of the AZ31(Mg-3 Al-1 Zn,wt.%)alloy after friction stir welding(FSW)and subsequent annealing at 400℃for 1 h was characterized by scanning electron micr...The difference in the microstructure,texture in the stir zone(SZ)of the AZ31(Mg-3 Al-1 Zn,wt.%)alloy after friction stir welding(FSW)and subsequent annealing at 400℃for 1 h was characterized by scanning electron microscopy(SEM)with electron backscatter diffraction(EBSD)measurements at the surface and core regions.The findings indicate that FSW produced grain refinement where the mean grain size decreases from 19μm(base metal)to 5.1 and 3.5μm at the surface and core regions,respectively.The c-axis of the grains at the surface region was aligned with the normal direction(<0001>//ND)due to the additional strain of the tool shoulder.In contrast,the core region shows a typical shear texture,where the c-axis tends to be oriented parallel to the welding direction(<0001>//WD).The Vickers microhardness mapping across the SZ revealed that the core region was soften than the surface region due to the dynamic recrystallization and texture weakening.The microstructure of the SZ remains principally deformed after annealing treatment except for the development of massive Mg_(17)Al_(12)precipitates and the abnormal grain growth of a few grains with<11-20>//WD orientation at the upper side of the surface region.The c-axis of the grains at the surface region was tilted about 10°toward WD,while an inclined<0001>//WD orientation about 30°from WD was developed at the core region.Consequently,the distribution of microhardness values across the SZ was more heterogeneous than the FSW sample.The results were discussed in the light of grain boundary misorientation,dislocation density and the pinning effect of Mg_(17)Al_(12)precipitates.Additionally,Schmid factor analysis was used to examine the activation of the basal slip mode to characterize the associated mechanical response.展开更多
The corrosion behaviour of as-cast binary Mg–0.3 Ce,Mg–1.44 Nd,Mg–0.63 Gd and Mg–0.41 Dy(wt%)alloys was investigated in DMEM+10%FBS solution using electrochemical and weight loss tests.The results revealed that th...The corrosion behaviour of as-cast binary Mg–0.3 Ce,Mg–1.44 Nd,Mg–0.63 Gd and Mg–0.41 Dy(wt%)alloys was investigated in DMEM+10%FBS solution using electrochemical and weight loss tests.The results revealed that the alloys with heavy RE elements(Gd and Dy)exhibited the lowest corrosion rate compared to the alloys with light RE elements(Ce and Nd).The cytocompatibility of the Mg–RE alloys was assessed via live/dead straining after 3 and 7 days.The results show that Mg–0.63 Gd alloy is a suitable candidate for biomedical applications.展开更多
The microstructure and texture development in a Mg-0.41Dy(wt%)alloy after plane strain compression(PSC)at 300℃under a strain rate of 10^(-2)and 10^(-4)s^(-1),up a final true strain of—1.2 were investigated using ele...The microstructure and texture development in a Mg-0.41Dy(wt%)alloy after plane strain compression(PSC)at 300℃under a strain rate of 10^(-2)and 10^(-4)s^(-1),up a final true strain of—1.2 were investigated using electron backscatter diffraction(EBSD)and X-ray diffraction.At high strain rate of 10^(-2)s^(-1),the microstructure exhibited massive twins mainly{101^(-)2}extension,{1011}contraction and{101^(-)3}-{101^(-)2}double twin due to the random texture of the as-cast alloy.Meanwhile,at a low strain rate of 10^(-4)s^(-1),the microstructure was characterized by dynamic recrystallization at the{101^(-)2}extension,(101^(-)1)contraction twins and grain boundaries.Twin dynamic recrystallization(TDRX),rotational dynamic recrystallization(RDRX)and discontinuous dynamic recrystallization(DDRX)were the main mechanisms responsible for the formation of recrystallized grains.The texture was characterized by the formation of three fibers:basal<0001>,<101^(-)0>//CD and<112^(-)0>//CD where CD is the compression direction.Moreover,the texture was less sensitive to the deformation conditions since the recrystallized grains showed the same orientation than twins.The changes of the mechanical properties of the alloy were ascribed to the resulting microstructure due to the twinning and dynamic recrystallization.展开更多
基金supported by the PHC-Tassili program No.24MDU114。
文摘The difference in the microstructure,texture in the stir zone(SZ)of the AZ31(Mg-3 Al-1 Zn,wt.%)alloy after friction stir welding(FSW)and subsequent annealing at 400℃for 1 h was characterized by scanning electron microscopy(SEM)with electron backscatter diffraction(EBSD)measurements at the surface and core regions.The findings indicate that FSW produced grain refinement where the mean grain size decreases from 19μm(base metal)to 5.1 and 3.5μm at the surface and core regions,respectively.The c-axis of the grains at the surface region was aligned with the normal direction(<0001>//ND)due to the additional strain of the tool shoulder.In contrast,the core region shows a typical shear texture,where the c-axis tends to be oriented parallel to the welding direction(<0001>//WD).The Vickers microhardness mapping across the SZ revealed that the core region was soften than the surface region due to the dynamic recrystallization and texture weakening.The microstructure of the SZ remains principally deformed after annealing treatment except for the development of massive Mg_(17)Al_(12)precipitates and the abnormal grain growth of a few grains with<11-20>//WD orientation at the upper side of the surface region.The c-axis of the grains at the surface region was tilted about 10°toward WD,while an inclined<0001>//WD orientation about 30°from WD was developed at the core region.Consequently,the distribution of microhardness values across the SZ was more heterogeneous than the FSW sample.The results were discussed in the light of grain boundary misorientation,dislocation density and the pinning effect of Mg_(17)Al_(12)precipitates.Additionally,Schmid factor analysis was used to examine the activation of the basal slip mode to characterize the associated mechanical response.
基金supported by the PRFU national project under Grant Agreement No.B00L02UN280120180005
文摘The corrosion behaviour of as-cast binary Mg–0.3 Ce,Mg–1.44 Nd,Mg–0.63 Gd and Mg–0.41 Dy(wt%)alloys was investigated in DMEM+10%FBS solution using electrochemical and weight loss tests.The results revealed that the alloys with heavy RE elements(Gd and Dy)exhibited the lowest corrosion rate compared to the alloys with light RE elements(Ce and Nd).The cytocompatibility of the Mg–RE alloys was assessed via live/dead straining after 3 and 7 days.The results show that Mg–0.63 Gd alloy is a suitable candidate for biomedical applications.
基金the PRFU national project under Grant Agreement No.B00L02UN280120180005.
文摘The microstructure and texture development in a Mg-0.41Dy(wt%)alloy after plane strain compression(PSC)at 300℃under a strain rate of 10^(-2)and 10^(-4)s^(-1),up a final true strain of—1.2 were investigated using electron backscatter diffraction(EBSD)and X-ray diffraction.At high strain rate of 10^(-2)s^(-1),the microstructure exhibited massive twins mainly{101^(-)2}extension,{1011}contraction and{101^(-)3}-{101^(-)2}double twin due to the random texture of the as-cast alloy.Meanwhile,at a low strain rate of 10^(-4)s^(-1),the microstructure was characterized by dynamic recrystallization at the{101^(-)2}extension,(101^(-)1)contraction twins and grain boundaries.Twin dynamic recrystallization(TDRX),rotational dynamic recrystallization(RDRX)and discontinuous dynamic recrystallization(DDRX)were the main mechanisms responsible for the formation of recrystallized grains.The texture was characterized by the formation of three fibers:basal<0001>,<101^(-)0>//CD and<112^(-)0>//CD where CD is the compression direction.Moreover,the texture was less sensitive to the deformation conditions since the recrystallized grains showed the same orientation than twins.The changes of the mechanical properties of the alloy were ascribed to the resulting microstructure due to the twinning and dynamic recrystallization.
