Magnesium alloy thin-walled cylindrical components with the advantages of high specific stiffness and strength present broad prospect for the lightweight of aerospace components.However,poor formability resulting from...Magnesium alloy thin-walled cylindrical components with the advantages of high specific stiffness and strength present broad prospect for the lightweight of aerospace components.However,poor formability resulting from the hexagonal close-packed crystal structure in magnesium alloy puts forwards a great challenge for thin-walled cylindrical components fabrication,especially for extreme structure with the thicknesschanging web and the high thin-wall.In this research,an ZK61 magnesium alloy thin-walled cylindrical component was successfully fabricated by two-step forging,i.e.,the pre-forging and final-forging is mainly used for wed and thin-wall formation,respectively.Microstructure and mechanical properties at the core,middle and margin of the web and the thin-wall of the pre-forged and final-forged components are studied in detail.Due to the large strain-effectiveness and metal flow along the radial direction(RD),the grains of the web are all elongated along RD for the pre-forged component,where an increasingly elongated trend is found from the core to the margin of the wed.A relatively low recrystallized degree occurs during pre-forging,and the web at different positions are all with prismatic and pyramid textures.During finalforging,the microstructures of the web and the thin-wall are almost equiaxed due to the remarkable occurrence of dynamic recrystallization.Similarity,except for few basal texture of the thin-wall,only prismatic and pyramid textures are found for the final-forged component.Compared with the initial billet,an obviously improved mechanical isotropy is achieved during pre-forging,which is well-maintained during final-forging.展开更多
6 mm thick AZ91 casting alloy plates were subjected to normal friction stir processing(NFSP,in air)and submerged friction stir processing(SFSP,under water),and microstructures and tensile properties of the experimenta...6 mm thick AZ91 casting alloy plates were subjected to normal friction stir processing(NFSP,in air)and submerged friction stir processing(SFSP,under water),and microstructures and tensile properties of the experimental materials were investigated.After FSP,the coarse microstructures in the as-cast condition are replaced by fine and equiaxed grains and the network-like eutecticβ-Mg_(17)Al_(12)phases disappear and are changed into particles pinned at the grain boundaries.SFSP results in further grain refinement in comparison with NFSP,and the average grain sizes of the NFSP and SFSP alloys are 8.4±1.3 and 2.8±0.8µm,respectively.XRD results reveal that the intensity ofβ-Mg_(17)Al_(12)diffraction peaks in the SFSP specimen decreases compared with NFSP.Due to significant grain refinement,the tensile strength and elongation of the SFSP AZ91 alloy are increased from 262 MPa and 18.9%for the NFSP material to 282 MPa and 25.4%,and the tensile strength(282 MPa)is nearly three times that of the BM(105 MPa).SFSP is an effective approach to refine the grain size and enhance the tensile properties of AZ91 casting alloy.展开更多
AIM：To study the effects of intraocular lens（IOL） explantation and demographic characteristics.METHODS：Retrospective non-comparative case series.Clinical data recorded from patient charts included the following：d...AIM：To study the effects of intraocular lens（IOL） explantation and demographic characteristics.METHODS：Retrospective non-comparative case series.Clinical data recorded from patient charts included the following：demographic,preoperative and postoperative characteristics;complications;surgical methods,and changes in visual acuity.RESULTS：A total of 69 eyes in 67 Chinese patients who received IOL explants were studied.The patients＇ mean age at the time of explantation was 46.1 years old [SD 22.5（6-85）],and 37 patients were female（55.2%）.Regarding employment,47.8% were farmers,23.9% were retired,16.4% were students,4.5% were unemployed,3% were workers,and 4.5% were other（including staff members,teachers and officers）.The main reasons for explantation were dislocation/decentration in 41 cases（59.4%） and retinal detachment in 10 cases（14.5%）.The third most prevalent cause was incorrect lens power in 7 eyes（10.1%）.The remaining reasons were endophthalmitis in 6 cases（8.7%）,posterior capsular opacity in 3 eyes（4.3%）,and impacting retinal surgery operation in 2 cases（2.9%）.The main comorbidities were high myopia in 18 eyes（26.1%）,trauma in 8 eyes（11.6%）,retinal detachment in 6 eyes（8.7%）,congenital cataracts in 8 eyes（11.6%）,and Marfan＇s syndrome in 2 eyes（2.9%）.The mean time from implantation to explantation was 4.0y [SD 4.2（0.005-15）].Treatment after explantation included posterior chamber IOL implantation in 44 eyes（63.8%） and aphakia in 25 eyes（36.2%）.After surgery,the best corrected visual ability（BCVA） was improved in 50 cases（72.5%）,including 28 patients（40.6%） in whom visual ability was improved by more than two lines.CONCLUSION：Dislocation/decentration is the main cause for explantation,and high myopia is a main risk factor.Posterior chamber IOL implantation remains the most elected treatment after explantation.展开更多
Mg-3.99Y-3.81Nd-0.53 Zr(WE43)casting alloy was subjected to single-pass friction stir processing(FSP)at a constant processing speed of 60 mm-min^(-1)and various rotation speeds of 400,800,1200,and 1500 r·min^(-1)...Mg-3.99Y-3.81Nd-0.53 Zr(WE43)casting alloy was subjected to single-pass friction stir processing(FSP)at a constant processing speed of 60 mm-min^(-1)and various rotation speeds of 400,800,1200,and 1500 r·min^(-1),and microstructures and mechanical properties of the experimental materials were investigated.FSP results in the generation of fine-grained microstructure,and fundamental breakage and dissolution of the coarse second phases.With the rotation speeds increasing,the average grain size of the FSP specimen in the stir zone first decreases and then increases,and the finest microstructure(~2μm)was prepared at the rotation speed of 800 r·min^(-1).Owing to the finer and more uniform microstructure,the mechanical properties of WE43 alloy after FSP are significantly improved.The variation tendency of the tensile properties is consistent with the change of the grain size.The maximum tensile strength,elongation,and average microhardness of the FSP WE43 alloy obtained at 800 r·min^(-1)are 290 MPa,17.2%,and HV92.9,respectively.The fracture morphology shows that small dimples can be observed on the FSP specimens,while the as-cast alloy fails through cleavage fracture.展开更多
BACKGROUND Suprachoroidal hemorrhage(SCH) is a rare but potentially catastrophic ocular event. Surgery for SCH is often challenging because of the difficulty in resolving the retinal and choroidal detachment. Here, we...BACKGROUND Suprachoroidal hemorrhage(SCH) is a rare but potentially catastrophic ocular event. Surgery for SCH is often challenging because of the difficulty in resolving the retinal and choroidal detachment. Here, we describe a novel surgical technique in which urokinase is administered by sub-Tenon's injection to target an organized clot in SCH prior to drainage.CASE SUMMARY A consecutive case series of four eyes with serous and hemorrhagic choroidal detachments secondary to cataract surgery or trauma was documented to evaluate the feasibility of using a sub-Tenon's urokinase injection-assisted 23-gauge and 20-gauge incision to drain choroidal detachments. Urokinase(2000 IU) was given by sub-Tenon's injection one day before surgery for clot liquefaction. A 23-gauge infusion line was placed in the anterior chamber. A 20-gauge incision was created in the suprachoroidal space 3.5 mm from the limbus. After drainage, pars plana vitrectomy was performed because of concomitant pathology that demanded this additional procedure. Visual acuity, ocular findings, the timing of surgical interventions, surgical procedures, and outcomes were retrospectively reviewed in four patients. Postoperative follow-up of the patients ranged from 6 to 24 mo(mean, 13 mo). After the treatment, all patients achieved excellent anatomical recovery. CONCLUSION Sub-Tenon's urokinase injection-assisted vitrectomy makes clot liquefaction happen in the early treatment stage, resulting in marked stability during the procedure.展开更多
Al7075 sheets are widely used in aerospace industry and their higher strength-plasticity collaborative improvement requirement is urgent.In this study,the microstructure inheriting the evolution and me-chanical proper...Al7075 sheets are widely used in aerospace industry and their higher strength-plasticity collaborative improvement requirement is urgent.In this study,the microstructure inheriting the evolution and me-chanical properties of Al7075 sheets during multidirectional rotary forging(MRF)and T6 heat treatment are analyzed.The results show that the average grain size exhibits near-parabolic evolution with increas-ing MRF deformation amount.MRF20%+T6(20%MRF deformation amount+T6)condition possesses the largest grain size of 72.6μm,and its abnormal grain growth mechanism is that the medium deformation energy and high deformation heterogeneity in MRF20%deformed grains could cause asynchronous re-crystallization behavior during T6 heat treatment,and the grains with comparatively higher deformation energy get recrystallized firstly and devour adjacent grains along preferred011or223misorientation axis.MRF70%+T6 condition possesses the finest grain size of 14.2μm,and its fine grain inheriting mech-anism is that the uniformly high deformation energy in MRF70%deformed grains causes uniformly rapid recrystallization,and rapidly recrystallized grains effectively suppress grain boundary motion from adja-cent grains.With increasing MRF deformation amount,tensile strength and elongation values both exhibit near-antiparabolic evolution.MRF70%+T6 condition possesses the largest tensile strength(563 MPa)and elongation(17.73%),which increases by 8.27%and 80.55%compared to as-annealed+T6(MRF0%+T6)condition(tensile strength is 520 MPa and elongation is 9.82%),respectively.The strength-plasticity col-laborative improvement is mainly because the combination of effectively inherited fine grains,refined inclusion particles,and uniformly distributed fineη’particles after T6 heat treatment could promote smooth dislocation movement and coordinated slip behavior in most matrix grains,which contributes to the delay of stress localization and strength-plasticity collaborative improvement.展开更多
High performance is of great importance to expand the application of magnesium alloys,and the inherent strength-plasticity synergic mechanism during a specific process should be unveiled.In this paper,a multi-degrees ...High performance is of great importance to expand the application of magnesium alloys,and the inherent strength-plasticity synergic mechanism during a specific process should be unveiled.In this paper,a multi-degrees of freedom(multi-DOF)forming process is conducted on initially extruded AZ91 magnesium alloy at different deformation degrees,including small deformation with deformation amounts of 10%and 20%,medium deformation with deformation amounts of 30%and 40%,and large deformation with deformation amounts of 60%and 70%.Simultaneous enhancement of ultimate tensile strength(UTS)and plasticity is achieved in all these multi-DOF processed alloys in comparison to the initially extruded one.As deformation degrees increase,both UTS and elongation of the multi-DOF processed alloy gradually increase in small and medium deformation and then slightly decrease in large deforma-tion,exhibiting a superior strength(401 MPa)and plasticity(16.3%)combination at deformation amount of 40%.The evolution of mechanical properties varying with deformation degrees is closely dependent on microstructure and texture characterization.The microstructures of multi-DOF processed AZ91 alloy are increasingly refined and heterogeneous as deformation degrees gradually increase,which consist of the predominant equiaxed coarse grains(CGs)and a few fine grains(FGs)in small deformation,some CGs(equiaxed or slightly elongated)and some FGs in medium deformation,and some remarkably elongated CGs and the predominant FGs in large deformation.The area fraction of basal texture gradually decreases while that of prismatic texture gradually increases with increasing deformation degrees,finally resulting in a complete disappearance of basal texture at a deformation amount of 70%.Thus,the strength-plasticity synergic mechanism related to increasingly obvious heterogeneous structure,gradually refined microstructure,and gradually decreased basal texture contribute to the constantly simultaneous improvement of UTS and plasticity until in medium deformation,and the remarkably elongated CGs play a significant role in the slight decrease of UTS and plasticity in large deformation even with further increasing grain refinement and decreasing basal texture.This research provides an efficient and novel way to achieve strength-plasticity synergic magnesium alloy via optimizing microstructure and texture.展开更多
Al5A06 sheets by large cold plastic deformation usually have high strength but low plasticity,i.e.weak strength-plasticity matching,which may lead to their poor fatigue property.In this study,annealing treat-ments are...Al5A06 sheets by large cold plastic deformation usually have high strength but low plasticity,i.e.weak strength-plasticity matching,which may lead to their poor fatigue property.In this study,annealing treat-ments are applied on cold rotary forged Al5A06 sheets to regulate strength-plasticity matching and im-prove fatigue properties.The microstructures,tensile mechanical properties and fatigue properties un-der different annealing parameters were analyzed.The abnormal grain growth mechanism of cold rotary forged Al5A06 sheets during 300℃ annealing treatment was investigated,and the fatigue failure mech-anism of Al5A06 sheets with different annealing temperatures was also investigated.The abnormal grain growth during 300℃ annealing treatment is mainly due to the asynchronous recrystallization behavior with low recrystallization driving force,which leads to the early recrystallized regions directly absorb-ing adjacent grains along134crystal direction.The cold rotary forged Al5A06 sheets after 250℃-2 h annealing treatment exhibit the best fatigue property,which is mainly because the optimum strength-plasticity matching brings about coordinate plastic deformation throughout most grains,and the effective dislocation movement between adjacent grains can delay the appearance of strain localization and ac-commodate continuous fatigue cyclic loading.展开更多
基金supported by the National Natural Science Foundation of China(No.52405408,No.U21A20131,No.U2037204,No.52422510)the Natural Science Foundation of Hubei Province(No.2023AFB116)+1 种基金the State Key Laboratory of Materials Processing and Die&Mould TechnologyHuazhong University of Science and Technology(No.P2022-005)。
文摘Magnesium alloy thin-walled cylindrical components with the advantages of high specific stiffness and strength present broad prospect for the lightweight of aerospace components.However,poor formability resulting from the hexagonal close-packed crystal structure in magnesium alloy puts forwards a great challenge for thin-walled cylindrical components fabrication,especially for extreme structure with the thicknesschanging web and the high thin-wall.In this research,an ZK61 magnesium alloy thin-walled cylindrical component was successfully fabricated by two-step forging,i.e.,the pre-forging and final-forging is mainly used for wed and thin-wall formation,respectively.Microstructure and mechanical properties at the core,middle and margin of the web and the thin-wall of the pre-forged and final-forged components are studied in detail.Due to the large strain-effectiveness and metal flow along the radial direction(RD),the grains of the web are all elongated along RD for the pre-forged component,where an increasingly elongated trend is found from the core to the margin of the wed.A relatively low recrystallized degree occurs during pre-forging,and the web at different positions are all with prismatic and pyramid textures.During finalforging,the microstructures of the web and the thin-wall are almost equiaxed due to the remarkable occurrence of dynamic recrystallization.Similarity,except for few basal texture of the thin-wall,only prismatic and pyramid textures are found for the final-forged component.Compared with the initial billet,an obviously improved mechanical isotropy is achieved during pre-forging,which is well-maintained during final-forging.
基金This work was sponsored by the Fundamental Research Funds for the Central Universities(No.2014ZG0028)Research Fund for the Doctoral Program of Higher Education of China(No.20130172110044).
文摘6 mm thick AZ91 casting alloy plates were subjected to normal friction stir processing(NFSP,in air)and submerged friction stir processing(SFSP,under water),and microstructures and tensile properties of the experimental materials were investigated.After FSP,the coarse microstructures in the as-cast condition are replaced by fine and equiaxed grains and the network-like eutecticβ-Mg_(17)Al_(12)phases disappear and are changed into particles pinned at the grain boundaries.SFSP results in further grain refinement in comparison with NFSP,and the average grain sizes of the NFSP and SFSP alloys are 8.4±1.3 and 2.8±0.8µm,respectively.XRD results reveal that the intensity ofβ-Mg_(17)Al_(12)diffraction peaks in the SFSP specimen decreases compared with NFSP.Due to significant grain refinement,the tensile strength and elongation of the SFSP AZ91 alloy are increased from 262 MPa and 18.9%for the NFSP material to 282 MPa and 25.4%,and the tensile strength(282 MPa)is nearly three times that of the BM(105 MPa).SFSP is an effective approach to refine the grain size and enhance the tensile properties of AZ91 casting alloy.
基金Supported by the National Natural Science Foundation of China Grant(No.81273902)the Project of Science and Technology of Social Development Funding(No.2016SF-100)+1 种基金the Construction Program of Xi’an Key Discipline Superiority Specialty(No.[2015]228-7)the Science and Technology Research and Development Program of Shaanxi Province(No.2014K11-03-07-04)
文摘AIM：To study the effects of intraocular lens（IOL） explantation and demographic characteristics.METHODS：Retrospective non-comparative case series.Clinical data recorded from patient charts included the following：demographic,preoperative and postoperative characteristics;complications;surgical methods,and changes in visual acuity.RESULTS：A total of 69 eyes in 67 Chinese patients who received IOL explants were studied.The patients＇ mean age at the time of explantation was 46.1 years old [SD 22.5（6-85）],and 37 patients were female（55.2%）.Regarding employment,47.8% were farmers,23.9% were retired,16.4% were students,4.5% were unemployed,3% were workers,and 4.5% were other（including staff members,teachers and officers）.The main reasons for explantation were dislocation/decentration in 41 cases（59.4%） and retinal detachment in 10 cases（14.5%）.The third most prevalent cause was incorrect lens power in 7 eyes（10.1%）.The remaining reasons were endophthalmitis in 6 cases（8.7%）,posterior capsular opacity in 3 eyes（4.3%）,and impacting retinal surgery operation in 2 cases（2.9%）.The main comorbidities were high myopia in 18 eyes（26.1%）,trauma in 8 eyes（11.6%）,retinal detachment in 6 eyes（8.7%）,congenital cataracts in 8 eyes（11.6%）,and Marfan＇s syndrome in 2 eyes（2.9%）.The mean time from implantation to explantation was 4.0y [SD 4.2（0.005-15）].Treatment after explantation included posterior chamber IOL implantation in 44 eyes（63.8%） and aphakia in 25 eyes（36.2%）.After surgery,the best corrected visual ability（BCVA） was improved in 50 cases（72.5%）,including 28 patients（40.6%） in whom visual ability was improved by more than two lines.CONCLUSION：Dislocation/decentration is the main cause for explantation,and high myopia is a main risk factor.Posterior chamber IOL implantation remains the most elected treatment after explantation.
基金the Fundamental Research Funds for the Central Universities(No.2012ZZ0051)。
文摘Mg-3.99Y-3.81Nd-0.53 Zr(WE43)casting alloy was subjected to single-pass friction stir processing(FSP)at a constant processing speed of 60 mm-min^(-1)and various rotation speeds of 400,800,1200,and 1500 r·min^(-1),and microstructures and mechanical properties of the experimental materials were investigated.FSP results in the generation of fine-grained microstructure,and fundamental breakage and dissolution of the coarse second phases.With the rotation speeds increasing,the average grain size of the FSP specimen in the stir zone first decreases and then increases,and the finest microstructure(~2μm)was prepared at the rotation speed of 800 r·min^(-1).Owing to the finer and more uniform microstructure,the mechanical properties of WE43 alloy after FSP are significantly improved.The variation tendency of the tensile properties is consistent with the change of the grain size.The maximum tensile strength,elongation,and average microhardness of the FSP WE43 alloy obtained at 800 r·min^(-1)are 290 MPa,17.2%,and HV92.9,respectively.The fracture morphology shows that small dimples can be observed on the FSP specimens,while the as-cast alloy fails through cleavage fracture.
基金Supported by the Project of Science and Technology of Social Development Fund of Shaanxi Province,No.2016SF-100 and No.2016SF-133Xi’an No.4 Hospital Research Incubation Fund,No.2018LH-2
文摘BACKGROUND Suprachoroidal hemorrhage(SCH) is a rare but potentially catastrophic ocular event. Surgery for SCH is often challenging because of the difficulty in resolving the retinal and choroidal detachment. Here, we describe a novel surgical technique in which urokinase is administered by sub-Tenon's injection to target an organized clot in SCH prior to drainage.CASE SUMMARY A consecutive case series of four eyes with serous and hemorrhagic choroidal detachments secondary to cataract surgery or trauma was documented to evaluate the feasibility of using a sub-Tenon's urokinase injection-assisted 23-gauge and 20-gauge incision to drain choroidal detachments. Urokinase(2000 IU) was given by sub-Tenon's injection one day before surgery for clot liquefaction. A 23-gauge infusion line was placed in the anterior chamber. A 20-gauge incision was created in the suprachoroidal space 3.5 mm from the limbus. After drainage, pars plana vitrectomy was performed because of concomitant pathology that demanded this additional procedure. Visual acuity, ocular findings, the timing of surgical interventions, surgical procedures, and outcomes were retrospectively reviewed in four patients. Postoperative follow-up of the patients ranged from 6 to 24 mo(mean, 13 mo). After the treatment, all patients achieved excellent anatomical recovery. CONCLUSION Sub-Tenon's urokinase injection-assisted vitrectomy makes clot liquefaction happen in the early treatment stage, resulting in marked stability during the procedure.
基金supported by the National Natural Science Foundation of China(No.U21A20131)the Technical Development Project of COMAC Shanghai Aircraft Manufacturing Co.,Ltd.(No.COMAC-SFGS-2023-631)the 111 Project(No.B17034),andthe In-novative Research Team Development Program of Ministry of Edu-cation of China(No.IRT17R83).
文摘Al7075 sheets are widely used in aerospace industry and their higher strength-plasticity collaborative improvement requirement is urgent.In this study,the microstructure inheriting the evolution and me-chanical properties of Al7075 sheets during multidirectional rotary forging(MRF)and T6 heat treatment are analyzed.The results show that the average grain size exhibits near-parabolic evolution with increas-ing MRF deformation amount.MRF20%+T6(20%MRF deformation amount+T6)condition possesses the largest grain size of 72.6μm,and its abnormal grain growth mechanism is that the medium deformation energy and high deformation heterogeneity in MRF20%deformed grains could cause asynchronous re-crystallization behavior during T6 heat treatment,and the grains with comparatively higher deformation energy get recrystallized firstly and devour adjacent grains along preferred011or223misorientation axis.MRF70%+T6 condition possesses the finest grain size of 14.2μm,and its fine grain inheriting mech-anism is that the uniformly high deformation energy in MRF70%deformed grains causes uniformly rapid recrystallization,and rapidly recrystallized grains effectively suppress grain boundary motion from adja-cent grains.With increasing MRF deformation amount,tensile strength and elongation values both exhibit near-antiparabolic evolution.MRF70%+T6 condition possesses the largest tensile strength(563 MPa)and elongation(17.73%),which increases by 8.27%and 80.55%compared to as-annealed+T6(MRF0%+T6)condition(tensile strength is 520 MPa and elongation is 9.82%),respectively.The strength-plasticity col-laborative improvement is mainly because the combination of effectively inherited fine grains,refined inclusion particles,and uniformly distributed fineη’particles after T6 heat treatment could promote smooth dislocation movement and coordinated slip behavior in most matrix grains,which contributes to the delay of stress localization and strength-plasticity collaborative improvement.
基金supported by the Natural Science Foundation of China(No.U21A20131)the Natural Science Foundation of Hubei Province(No.2023AFB116)+2 种基金the State Key Laboratory of Materials Processing and Die&Mould Technology,Huazhong University of Science and Technology(No.P2022-005)the 111 Project(No.B17034)Innovative Research Team Development Program of Ministry of Education of China(No.IRT17R83).
文摘High performance is of great importance to expand the application of magnesium alloys,and the inherent strength-plasticity synergic mechanism during a specific process should be unveiled.In this paper,a multi-degrees of freedom(multi-DOF)forming process is conducted on initially extruded AZ91 magnesium alloy at different deformation degrees,including small deformation with deformation amounts of 10%and 20%,medium deformation with deformation amounts of 30%and 40%,and large deformation with deformation amounts of 60%and 70%.Simultaneous enhancement of ultimate tensile strength(UTS)and plasticity is achieved in all these multi-DOF processed alloys in comparison to the initially extruded one.As deformation degrees increase,both UTS and elongation of the multi-DOF processed alloy gradually increase in small and medium deformation and then slightly decrease in large deforma-tion,exhibiting a superior strength(401 MPa)and plasticity(16.3%)combination at deformation amount of 40%.The evolution of mechanical properties varying with deformation degrees is closely dependent on microstructure and texture characterization.The microstructures of multi-DOF processed AZ91 alloy are increasingly refined and heterogeneous as deformation degrees gradually increase,which consist of the predominant equiaxed coarse grains(CGs)and a few fine grains(FGs)in small deformation,some CGs(equiaxed or slightly elongated)and some FGs in medium deformation,and some remarkably elongated CGs and the predominant FGs in large deformation.The area fraction of basal texture gradually decreases while that of prismatic texture gradually increases with increasing deformation degrees,finally resulting in a complete disappearance of basal texture at a deformation amount of 70%.Thus,the strength-plasticity synergic mechanism related to increasingly obvious heterogeneous structure,gradually refined microstructure,and gradually decreased basal texture contribute to the constantly simultaneous improvement of UTS and plasticity until in medium deformation,and the remarkably elongated CGs play a significant role in the slight decrease of UTS and plasticity in large deformation even with further increasing grain refinement and decreasing basal texture.This research provides an efficient and novel way to achieve strength-plasticity synergic magnesium alloy via optimizing microstructure and texture.
基金financially supported by the National Natural Science Foundation of China(no.U21A20131)the Innovative Research Team Development Program of Ministry of Education of China(no.IRT17R83)for the support given to this research.
文摘Al5A06 sheets by large cold plastic deformation usually have high strength but low plasticity,i.e.weak strength-plasticity matching,which may lead to their poor fatigue property.In this study,annealing treat-ments are applied on cold rotary forged Al5A06 sheets to regulate strength-plasticity matching and im-prove fatigue properties.The microstructures,tensile mechanical properties and fatigue properties un-der different annealing parameters were analyzed.The abnormal grain growth mechanism of cold rotary forged Al5A06 sheets during 300℃ annealing treatment was investigated,and the fatigue failure mech-anism of Al5A06 sheets with different annealing temperatures was also investigated.The abnormal grain growth during 300℃ annealing treatment is mainly due to the asynchronous recrystallization behavior with low recrystallization driving force,which leads to the early recrystallized regions directly absorb-ing adjacent grains along134crystal direction.The cold rotary forged Al5A06 sheets after 250℃-2 h annealing treatment exhibit the best fatigue property,which is mainly because the optimum strength-plasticity matching brings about coordinate plastic deformation throughout most grains,and the effective dislocation movement between adjacent grains can delay the appearance of strain localization and ac-commodate continuous fatigue cyclic loading.
