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13篇 您的检索式:作者名="S.KAMADO"
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1Enhancing strength and creep resistance of Mg-Gd-Y-Zn-Zr alloy by substituting Mn for Zr显示文摘The age-hardening behavior and mechanical properties of the extruded Mg-2Gd-1.2Y-0.5Zn(at.%)alloy with Zr or Mn additions were investigated.The results show that Mn added alloy exhibits more remarkable age-hardening response than Zr added alloy,which is attributed to the fact that partitioning of Mn into the β'phases,β'precipitates and long period stacking ordered(LPSO)phases leads to the decrement in(G d+Y)concentrations in the second phases,facilitating the precipitation during aging treatment.Both peak-aged alloys show bimodal microstructure comprising the fine DRXed grains with nano-sized β phases pinned at DRXed grain boundaries as well as coarse worked grains with strong fiber texture.High strength and good thermal stability were obtained in both peak-aged Mn and Zr added alloys.While the peak-aged Mn added alloy shows higher strength and superior creep resistance due to its denser β'precipitates,thin LPSO phases and γ'precipitates and higher area fraction of worked grains with strong fiber texture.The 0.2% tensile proof stress and ultimate tensile strength of peak-aged Mn added alloy reach up to 454 MPa and 508 MPa,respectively,with elongation of 3.2%at room temperature.The minimum creep rate of the peak-aged Mn added alloy at 250℃/150 MPa is 2.4 × 10^-8 s^-1,which is superior than previously reported extruded Mg-Gd based alloys.C.Xu T.Nakata G.H.Fan X.W.Li G.Z.Tang S.Kamado 2019Journal of Magnesium and Alloys2019,7,3:14
2Development of a high-strength Mg alloy with superior ductility through a unique texture modification from equal channel angular pressing显示文摘In the current study,a homogenous ultra-fine grained microstructure with average grain size of 1.0μm is achieved in the Mg-Zn-Ca-Mn alloy through the reduplicative equal channel angular pressing(ECAP)at 300℃,and the mechanical properties are remarkably improved,with room-temperature yield strength of 269.6 MPa and elongation of 22.7%.The twinning deformation results in a discontinuous recrystallization behavior in the initial stage of ECAP.With further deformation,the continuously dynamic recrystallization contributes to an obvious grain refinement effect.The activation of non-basal slip system leads to the formation of a unique basal texture,which is related to the elevated ECAP temperature and the decreased grain size.Both grain refinement and texture modification derived from ECAP process result in the increase of yield strength,while the cracked secondary phase particles are beneficial to the enhanced ductility,through reducing the stress concentration and hindering premature failure.L.B.Tong J.H.Chu W.T.Sun Z.H.Jiang D.N.Zou S.F.Liu S.Kamado M.Y.Zheng 2021Journal of Magnesium and Alloys2021,9,3:8
3Effect of forced-air cooling on the microstructure and age-hardening response of extruded Mg-Gd-Y-Zn-Zr alloy full with LPSO lamella显示文摘The homogenized Mg-8.2 Gd-3.8 Y-1.0 Zn-0.4 Zr(wt.%)alloy full of plate-shaped long period stacking ordered(LPSO)phases was hot extruded in the atmosphere and cooled by the forced-air,then the effect of forced-air cooling on the microstructure and age-hardening response of the alloy was investigated in this work.The results show that in comparison with the extruded sample cooling in the atmosphere,the forced-air cooling restricts dynamic recrystallization(DRX)and brings about finer dynamic recrystallized(DRXed)grain size,stronger basal texture and higher dislocation density.Furthermore,the forced-air cooling promotes the dynamic precipitation in the DRXed regions and facilitates formation of plate-shaped LPSO phases andγ’phases with smaller interspacing in the unrecrystallized(un DRXed)regions,then slightly restricts the precipitation ofβphases during aging.After peak-ageing treatment,the extruded sample with forced-air cooling shows superior tensile properties with a tensile yield strength of 439 MPa,an ultimate tensile strength of 493 MPa,and elongation to failure of 18.6%.S.Z.Wu T.Nakata G.Z.Tang C.Xu X.J.Wang X.W.Li X.G.Qiao M.Y.Zheng L.Geng S.Kamado G.H.Fan 2021Journal of Materials Science & Technology2021,,14:6
4Effect of hot extrusion on microstructure and mechanical properties of quasicrystal-reinforced Mg-Zn-Yalloy显示文摘The microstructure and mechanical properties of as-cast and as-extruded Mg-Zn-Y alloy (Mg-11%Zn-0.9%Y, mass fraction) containing Mg3YZn6 quasicrystal were studied. The eutectic icosahedral quasicrystal phase (I-phase) is broken and almost distributes along the extrusion direction, and fine I-phase with nano-size is precipitated during the extrusion. The α-Mg matrix grains are refined due to recrystallization occuring during the hot extrusion. Some {1012} twins are observed in the extruded ZW1101 alloy. And {0002}〈1010〉 fiber texture is formed in matrix alloys after hot extrusion. The extruded alloy exhibits high strength in combination with large elongation at room temperature. The strengthening mechanism of the as-extruded alloy was discussed.郑明毅 乔晓光 徐世伟 甘为民 吴昆 S.Kamado Y.Kojima H.G.Brokmeier 2005中国有色金属学会会刊:英文版2005,15,4:5
5Reducing the tension-compression yield asymmetry of extruded Mg-Zn-Ca alloy via equal channel angular pressing显示文摘The influence of equal channel angular pressing on the tension-compression yield asymmetry of extruded Mg-5.3 Zn-0.6 Ca(weight percent)alloy has been investigated.The microstructure was obviously refined by the large strain during the equal channel angular pressing,accompanied with very fine Ca_(2)Mg_(6)Zn_(3) phases with average diameter of 70 nm.The weak tension-compression yield asymmetry after equal channel angular pressing is mainly attributed to the reduced volume fraction of extension twinning during the compression,because the slope(k)of twinning in Hall-Petch relationship is higher than that of dislocation slip,and the twinning deformation is difficult to take place with decreasing grain size.The basal slip is more active in the alloy after equal channel angular pressing,due to the non-basal texture components,which hinders the twinning activation and reduces the yield asymmetry.Furthermore,the presence of fine precipitate restricts the twinning activation,which also contributes to the reduction of yield asymmetry.L.B.Tong M.Y.Zheng S.Kamado D.P.Zhang J.Meng L.R.Cheng H.J.Zhang 2015Journal of Magnesium and Alloys2015,3,4:5
6Improvement of strength and ductility synergy in a room-temperature stretch-formable Mg-Al-Mn alloy sheet by twin-roll casting and low-temperature annealing显示文摘Strength and ductility synergy in an Mg-3mass%Al-Mn(AM30)alloy sheet was successfully improved via twin-roll casting and annealing at low-temperature.An AM30 alloy sheet produced by twin-roll casting,homogenization,hot-rolling,and subsequent annealing at 170℃ for 64 h exhibits a good 0.2%proof stress of 170 MPa and a large elongation to failure of 33.1%along the rolling direction.The sheet also shows in-plane isotropic tensile properties,and the 0.2%proof stress and elongation to failure along the transverse direction are 176 MPa and 35.5%,respectively.Though the sheet produced by direct-chill casting also shows moderate strengths if the annealing condition is same,the direct-chill casting leads to the deteriorated elongation to failure of 23.9%and 30.0%for the rolling and transverse directions,respectively.As well as such excellent tensile properties,a high room-temperature stretch formability with an Index Erichsen value of 8.3 mm could be obtained in the twin-roll cast sheet annealed at 170℃ for 64 h.The annealing at a higher temperature further improves the stretch formability;however,this results in the decrease of the tensile properties.Microstructure characterization reveals that the excellent combination of strengths,ductility,and stretch formability in the twin-roll cast sheet annealed at the low-temperature annealing is mainly attributed to the uniform recrystallized microstructure,fine grain size,and circular distribution of(0001)poles away from the normal direction of the sheet.T.Nakata C.Xu K.Kaibe Y.Yoshida K.Yoshida S.Kamado 2022Journal of Magnesium and Alloys2022,10,4:5
7Quasi-in-situ observing the rare earth texture evolution in an extruded Mg-Zn-Gd alloy with bimodal microstructure显示文摘The static recrystallization and associated texture evolution were investigated in an extruded Mg-Zn-Gd alloy with bimodal microstructure based on a quasi-in-situ electron back-scatter diffraction(EBSD)method.The typical rare earth(RE)texture formed during annealing,evolving from the bimodal microstructure with[1010]basal fiber texture that consisted of fine recrystallized(RXed)grains and coarse unrecrystallized(un RXed)grains elongated along the extrusion direction.In both RXed and un RXed regions,the RXed nucleation produced randomized orientations without preferred selection and the RXed grains with RE texture orientation had more intensive growth ability than those with basal fiber orientation,thereby leading to the preferred selection of RE texture orientation during grain growth.The relationships between stored strain energy,solute drag,grain growth and texture evolution are discussed in detail.This study provided direct evidence of the RE texture evolution in an extruded Mg-RE alloy,which assists in understanding the formation mechanisms for RE texture during extrusion and better developing wrought Mg alloys with improved formability.M.G.Jiang C.Xu H.Yan T.Nakata Z.W.Chen C.S.Lao R.S.Chen S.Kamado E.H.Han 2021Journal of Magnesium and Alloys2021,9,5:4
8Dynamic microstructure evolution and mechanical properties of dilute Mg-Al-Ca-Mn alloy during hot rolling显示文摘The dynamic microstructure and texture of dilute Mg-0.50Al-0.71Ca-0.33Mn(wt.%) during hot rolling at two slab temperatures were investigated by electron backscattered diffraction(EBSD) and high resolution transmission electron microscopy(HRTEM). The results show that the development of the rolling microstructures is to first form {10–12} extension twins in the original grains, thereby forming the extension-twinned regions, and then to further form {10–11}-{10–12} double twins and kinks in the extension-twinned regions, and finally to form continuous dynamic recrystallized(continuous DRXed)grains in the double twins and the cross parts of the shear-deformed coarse extension-twinned regions.These extension twins, double twins and kinks show a decisive effect on the formation of rolling texture.The number of {10–11}-{10–12} double twins and resultant the continuous DRX process are strongly affected by the rolling slab temperature and the reduction thickness per pass. By optimizing the rolling conditions, texture and microstructures of the multi-pass rolled Mg-Al-Ca-Mn alloy sheets are successfully modified. Although the total alloy content is only 1.5 wt.%, these Mg-Al-Ca-Mn alloy sheets show much higher strength than the commercial Mg-3Al-1 Zn(wt.%)(AZ31B) sheet.Shiwei Xu Congcong Zhu Zhanhong Lin Chen Jin S.Kamado K.Oh-ishi Yun Qin 2022Journal of Materials Science & Technology2022,,34:2
9Simultaneously Enhanced Mechanical Properties and Damping Capacities of ZK60 Mg Alloys Processed by Multi-Directional Forging显示文摘In this study,the mechanical properties and damping capacities of cast Mg-5.5 Zn-0.6 Zr(weight percent,ZK60)alloys have been simultaneously improved by a facile multi-directional forging(MDF)processing,and the mechanisms of microstructure evolution and texture modification are systematically investigated.The activation of tension twinning occurs during the initial MDF stage,due to the coarse-grained structure of the as-cast alloy.With increasing MDF passes,the continuous dynamic recrystallization(CDRX)results in a fine equiaxed-grain structure.The typical non-basal texture is formed in the as-MDFed alloy for 6 passes,with the(0001)planes inclined 60°–70°to forged direction and 10°–20°to transverse direction,respectively.A good balance between the strength(~194.9 MPa)and ductility(~24.9%)has been achieved,which can be ascribed to the grain refinement,non-basal texture and fine precipitate particles.The damping capacity is remarkably improved after MDF processing,because the severe deformation increases the dislocation density,which effectively enlarges the sweep areas of mobile dislocations.L.B.Tong J.H.Chu D.N.Zou Q.Sun S.Kamado H.G.Brokmeier M.Y.Zheng 2021Acta Metallurgica Sinica(English Letters)2021,34,2:1
10Optimization of Cu content for the development of high-performance T5-treated thixo-cast Al-7Si-0.5Mg-Cu(wt.%)alloy显示文摘Cu content has been successfully optimized in a thixo-cast and directly aged(T5-treatment)Al-7 Si-0.5 Mg(wt.%)alloy.Even after the 0.5%Cu addition,plate-like Al_(2)Cu(θ’)phases,which contribute to high strengths and large plasticity,are precipitated.The formation of a large fraction of Cu-containing brittle phases could be suppressed as well.Then,the Al-7Si-0.5Mg-0.5Cu alloy exhibits high ultimate tensile strength,0.2%proof stress,and elongation to failure of 296 MPa,209 MPa,and 8.8%,respectively.This results in a high quality index similar to that of solution-treated and subsequently aged(T6-treated)Al-7 Si-Mg alloys.A Cu addition over 1.0%further improves the strengths;however,this leads to poor ductility because of the high fraction of Cu-containing brittle phases.K.Yamamoto M.Takahashi Y.Kamikubo Y.Sugiura S.Iwasawa T.Nakata S.Kamado 2021Journal of Materials Science & Technology2021,,34:1
11Origin of extension twinning-mediated static recrystallization and unique parallel alignment of(0001) poles to transverse direction in Mg-3Al-0.4Mn(mass%) alloy sheet显示文摘The origin of unique parallel alignment of(0001) poles to transverse direction(TD) was investigated using Mg-3Al-0.4Mn(mass%)alloy sheets rolled with different process conditions. When rolling was performed with intermediate reheating, the alloy showed a sluggish static recrystallization(SRX) behavior during post-annealing, facilitating the nucleation and growth of statically recrystallized grains from extension twins. This resulted in the apparent texture component with the parallel alignment of the(0001) poles to the TD, and the sheet exhibited good ductility for both the rolling direction(RD) and TD. In contrast, continuous rolling without intermediate reheating led to the formation of severely deformed regions near double twins. SRX was promoted at such regions, forming a typical basal textural feature with weak RD-split of the(0001) poles. Although extension twins were formed after the continuous rolling, SRX was facilitated at the severely deformed regions with double twins, and the formation of the unique alignment of the(0001) poles to the TD was suppressed. The RD-split texture led to the large elongation to failure along the RD, while it along the TD decreased owing to the narrow distribution of the(0001)poles toward the TD, resulting in the in-plane anisotropy in ductility.T.Nakata C.Xu L.Geng S.Kamado 2023Journal of Magnesium and Alloys2023,11,9:0
12Microstructure and mechanical properties of extruded Mg-6.5Gd-1.3Nd-0.7Y-0.3Zn alloy显示文摘The Mg-6.5Gd-1.3Nd-0.7Y-0.3Zn alloy ingot and sheet were prepared by casting and hot extrusion techniques,and the microstructure,age hardening behavior and mechanical properties were investigated.The results show that the as-cast alloy mainly containsα-Mg solid solution and compounds of Mg5RE and Mg24RE5(RE=Gd,Y and Nd)phases.The grain size is refined after hot extrusion,and the Mg5RE and Mg24RE5 compounds are broken during the extrusion process.The extruded alloy exhibits remarkable age hardening response and excellent mechanical properties in the peak-aging state.The ultimate tensile strength,yield strength and elongation are 310 MPa,201 MPa and 5.8%at room temperature,and 173 MPa,133 MPa and 25.0%at 300℃,respectively.侯秀丽 曹占义 张蕾蕾 房大庆 徐世伟 S.KAMADO 王立民 2010Transactions of Nonferrous Metals Society of China2010,20,B07:0
13Towards tailoring basal texture of rolled Mg alloy sheet by recrystallization for high room-temperature formability: A review显示文摘Room-temperature(RT) formability is a key factor to broaden the applications of rolled Mg alloy sheets in the industry. However, rolled Mg alloy sheets generally form strong basal texture, where the(0001) poles align parallel to the normal direction(ND). This hinders the activation of(0001) [1120] basal slip, limiting the RT formability. Therefore, texture weakening, i.e., the inclination of the(0001) poles from the ND, plays an important role to improve the RT formability. Recrystallization is crucial to control the textural development in Mg,and currently, the texture weakening is commonly achieved using static recrystallization(SRX). However, the type of slipping and twinning,which are activated during rolling, affect the textural features after SRX. It is also demonstrated that shear bands and preferential grain growth are important factors to tailor the texture during SRX. Indeed, dynamic recrystallization(DRX) easily occurs during rolling in Mg, which also affects the final rolling texture, while the effect of DRX on the textural formation is not extensively studied for the development of RT-formable Mg alloy sheets. Therefore, the effect of these factors on the textural development in rolled Mg is reviewed in this manuscript.Additionally, the ideal microstructure and texture for RT-formable Mg alloy sheets are still controversial. The RT-formability includes stretch forming(biaxial tension), bending(plane strain tension), and deep-drawing. In particular, the stretch forming is commonly used to evaluate the RT-formability of rolled Mg. Although the stretch formability has been improved by recent studies, the further improvement is necessary owing to the relatively low formability of rolled Mg compared with that of rolled Fe and Al. Based on the relationship between the microstructure/texture and stretch formability provided in the literature, the design guidance for high stretch formability is proposed in this review.T.Nakata S.Kamado 2023Journal of Magnesium and Alloys2023,11,11:0
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