20 results on '"Wu, K."'
Search Results
2. Influence of rolling temperature on the microstructure and mechanical properties of Mg–Gd–Y–Zn–Zr alloy sheets
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Xu, C., Zheng, M.Y., Wu, K., Wang, E.D., Fan, G.H., Xu, S.W., Kamado, S., Liu, X.D., Wang, G.J., and Lv, X.Y.
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ZIRCONIUM alloys , *ROLLING (Metalwork) , *METAL microstructure , *MECHANICAL properties of metals , *STRAINS & stresses (Mechanics) , *CRYSTAL grain boundaries , *PHASE distortion (Electronics) - Abstract
Abstract: The extruded Mg–8.2Gd–3.8Y–1.0Zn–0.4Zr (wt%) alloy were subjected to large-strain hot rolling with different final rolling temperatures. The microstructural evolution and mechanical properties of the sheets were investigated. The microstructure became homogeneous after hot rolling process and long period stacking ordered (LPSO) phase distributed at grain boundaries along rolling direction. The sheet rolled at 300°C was composed of deformed grains, substructures and excessive dislocations. With increasing final rolling temperatures from 300°C to 400°C, the volume fraction of recrystallized grains with relatively random orientations increased significantly. The strength of the rolled sheets was improved while the ductility was deteriorated with decreasing final rolling temperatures. The tensile yield strength and ultimate tensile strength of the sheet rolled at 300°C reached 320MPa and 416MPa, respectively with the elongation to failure of 5.3%. The mechanical anisotropy of the rolling sheet became unity when rolled at higher temperature of 400°C due to the formation of weaker basal texture. [Copyright &y& Elsevier]
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- 2013
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3. Effect of cooling rate on the microstructure evolution and mechanical properties of homogenized Mg–Gd–Y–Zn–Zr alloy
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Xu, C., Zheng, M.Y., Wu, K., Wang, E.D., Fan, G.H., Xu, S.W., Kamado, S., Liu, X.D., Wang, G.J., and Lv, X.Y.
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MANGANESE alloys , *COOLING , *METAL microstructure , *MECHANICAL properties of metals , *METAL quenching , *CRYSTAL grain boundaries , *PARTICLE size distribution , *STRENGTH of materials - Abstract
Abstract: Different cooling processes, such as quenching in warm water and cooling in furnace, were introduced to homogenize Mg–8.2Gd–3.8Y–1.0Zn–0.4Zr (wt%) alloy. Microstructure evolution and mechanical properties of the homogenized alloy were investigated. The as-quenched sample was comprised of α-Mg matrix, Mg5RE phase and 18R LPSO phase distributed at the grain boundaries and a few of RE-rich particles distributed randomly. During the process of cooling in furnace, Mg5RE and 18R LPSO phases were transformed into block-shaped 14H LPSO phase and lamellar-shaped 14H LPSO phase, respectively, due to the diffusion of solute atoms into the α-Mg matrix. Furthermore, the lamellar-shaped 14H LPSO phase grew and ran through the whole grains. The as-quenched sample exhibits tensile yield strength of 130MPa, ultimate tensile strength of 206MPa and elongation to failure of 5.5%, while the sample cooled in the furnace exhibits higher tensile yield strength but lower ultimate tensile strength and ductility due to the coarse grains and formation of block-shaped 14H LPSO phase. [Copyright &y& Elsevier]
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- 2013
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4. Effect of final rolling reduction on the microstructure and mechanical properties of Mg–Gd–Y–Zn–Zr alloy sheets
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Xu, C., Zheng, M.Y., Wu, K., Wang, E.D., Fan, G.H., Xu, S.W., Kamado, S., Liu, X.D., Wang, G.J., Lv, X.Y., Li, M.J., and Liu, Y.T.
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MANGANESE alloys , *ROLLING (Metalwork) , *METAL microstructure , *MECHANICAL properties of metals , *METALS , *CRYSTAL texture , *RECRYSTALLIZATION (Metallurgy) - Abstract
Abstract: The Mg–8.2Gd–3.8Y–1.0Zn–0.4Zr (wt.%) alloy was hot rolled with different final rolling reductions at 400°C. The microstructure evolution and texture of the sheets were analyzed, and their effect on the mechanical properties was discussed. All of the rolled sheets consist of fine dynamically recrystallized grains with almost random orientation, large deformed grains with strong basal texture. In addition, bent lamellar-shaped long period stacking ordered (LPSO) phases due to kink deformation were observed in the deformed grains. The volume fraction of the dynamic recrystallization increased with increasing final rolling reduction and the basal texture weakened gradually. The strength of the alloy sheets changed a little with increasing final rolling reduction, while the yield anisotropy and the ductility were significantly improved. The sheet final-rolled with thickness reduction of 60% exhibits tensile yield strength of 306MPa, ultimate tensile strength of 393MPa and elongation to failure of 14.6% at ambient temperature, and tensile yield strength of 264MPa, ultimate tensile strength of 345MPa and elongation to failure of 19.4% at 250°C. [Copyright &y& Elsevier]
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- 2013
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5. Microstructure and mechanical properties of the accumulative roll bonded (ARBed) pure magnesium sheet
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Chang, H., Zheng, M.Y., Wu, K., Gan, W.M., Tong, L.B., and Brokmeier, H.-G.
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METAL microstructure , *MECHANICAL properties of metals , *SHEET metal , *MAGNESIUM , *METAL bonding , *HEAT treatment of metals , *CRYSTAL texture , *METALS - Abstract
Abstract: The pure Mg sheets were processed by ARB at 400°C and 300°C up to 8 cycles and 4 cycles, respectively. The microstructure was refined during the first cycle and only homogenized during the following ARB process due to the high deformation temperature, intermediate reheating and air-cooling. The ARB process did not show an obvious effect on the tensile properties of the as-ARBed pure Mg sheet due to the stable grain size and dominant basal plane texture during ARB. Further deformation should be introduced to improve the bonding quality of the as-ARBed sheet. [ABSTRACT FROM AUTHOR]
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- 2010
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6. Microstructure and mechanical properties of WE43 magnesium alloy fabricated by direct-chill casting.
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Jiang, H.S., Zheng, M.Y., Qiao, X.G., Wu, K., Peng, Q.Y., Yang, S.H., Yuan, Y.H., and Luo, J.H.
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MAGNESIUM alloys , *INGOTS , *METAL microstructure , *MECHANICAL properties of metals , *METAL castings , *GRAIN size - Abstract
High quality WE43 magnesium alloy ingots with diameter of 500 mm are successfully fabricated by direct-chill (DC) casting. The alloying elements distributed almost homogeneously across the large ingot. With the average grain size decreasing from the center to the edge of the ingot, the mechanical properties are improved gradually. After solution treatment at 525 °C for 8 h, the Mg 14 Nd 2 Y phases distributing along the grain boundaries are well dissolved into matrix. The direct-chill (DC) casting ingot exhibits remarkable age-hardening response from 85 Hv to 117 Hv after T6 treatment at 250 °C. The T6 peak-aged sample exhibits ultimate tensile strength of 274 MPa, yield strength of 215 MPa and elongation to failure of 3.4%, which are higher than those of sand-cast and permanent mold cast WE43 alloys. The large amount of nano prismatic β ′ and β 1 phases precipitated during T6 treatment contribute to improved strength of the WE43 alloy. [ABSTRACT FROM AUTHOR]
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- 2017
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7. Effect of Ca/Al ratio on microstructure and mechanical properties of Mg-Al-Ca-Mn alloys.
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Li, Z.T., Zhang, X.D., Zheng, M.Y., Qiao, X.G., Wu, K., Xu, C., and Kamado, S.
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MAGNESIUM alloys , *CALCIUM , *MECHANICAL properties of metals , *METAL microstructure , *METAL extrusion , *STRENGTH of materials - Abstract
The effect of Ca/Al ratio on microstructure and mechanical properties of the as-cast and as-extruded Mg-Al-Ca-Mn alloys were investigated. The as-cast Mg-Al-Ca-Mn alloys with Ca/Al mass ratios less than 0.50 contain divorced and lamellar eutectic (Mg,Al) 2 Ca. When Ca/Al ratio is greater than 0.90, fine lamellar Mg 2 Ca phase is formed in the as-cast Mg-Al-Ca-Mn alloys. After extrusion, the second phases are broken and dispersed along the extrusion direction. The area fraction of DRXed regions decrease with increasing Ca/Al ratio, the microstructure changes from an almost fully recrystallized structure to a bimodal structure consisting of fine dynamically recrystallized (DRXed) grains and coarse deformed regions. With increasing Ca/Al ratio, the DRXed grains and dispersed second phases are refined. The as-extruded alloys exhibit a strong basal fiber texture, the intensity of which is increased with increasing Ca/Al ratio. With increasing Ca/Al ratio, the {0002}<11-20> texture component in the DRXed regions is suppressed, and shifted to a {0002}<10-10> texture component. The strength of the as-extruded Mg-Al-Ca-Mn alloys increases significantly with increasing Ca/Al ratio. The as-extruded Mg-2.7Al-3.5Ca-0.4Mn (wt%) alloy exhibits a tensile proof strength of 438 MPa and an ultimate tensile strength of 457 MPa. The extraordinary high strengths are attributed to the ultrafine DRXed grains pinned by fragmented secondary phases, strong basal texture and dense nano-scale precipitates. The present research indicates that the Mg-Al-Ca-Mn alloys have a great potential as next generation low-cost ultrahigh-strength wrought Mg alloys. [ABSTRACT FROM AUTHOR]
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- 2017
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8. Microstructure and tensile properties of SiC nanoparticles reinforced magnesium matrix composite prepared by multidirectional forging under decreasing temperature conditions.
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Nie, K.B., Wang, X.J., Xu, F.J., Wu, K., and Zheng, M.Y.
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METAL microstructure , *TENSILE strength , *SILICON carbide , *METAL nanoparticles , *MAGNESIUM alloys , *METALLIC composites , *TEMPERATURE effect , *FORGING - Abstract
Multidirectional forging (MDF) under decreasing temperature conditions was adopted to process SiC nanoparticles reinforced magnesium matrix composite. The results showed that grains of the nanocomposite were effectively refined while the amount of precipitated phases was significantly increased after MDF under decreasing temperature conditions. The precipitated phases as well as dispersed SiC nanoparticles could hinder the growth of dynamic recrystallization. The yield strength and ultimate tensile strength of the nanocomposites were increased compared with that of as-cast nanocomposite. This improvement could be attributed to obvious grain refinement as well as Orowan strengthening effect introduced by the dispersed SiC nanoparticles and the precipitated phases. Microcrack could initiate within the SiC nanoparticle dense zones during tensile test at room temperature, resulting in decrease of the elongation. [ABSTRACT FROM AUTHOR]
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- 2015
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9. The microstructure, texture and mechanical properties of extruded Mg–5.3Zn–0.2Ca–0.5Ce (wt%) alloy.
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Du, Y.Z., Qiao, X.G., Zheng, M.Y., Wu, K., and Xu, S.W.
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MAGNESIUM alloys , *METAL microstructure , *CRYSTAL texture , *MECHANICAL properties of metals , *METAL extrusion , *CRYSTAL grain boundaries - Abstract
Mg–5.3 wt%Zn alloy microalloyed with 0.2 wt%Ca and 0.5 wt%Ce was extruded, and the microstructure, texture and mechanical properties of the as-extruded alloy were investigated. The undissolved coarse T 1 ′during homogenization treatment stimulated nucleation of dynamic recrystallization (DRX) grains during extrusion. The double microalloying with Ca and Ce promoted the dynamic precipitation, resulting in high density precipitates after hot extrusion. Fine Ca 2 Mg 6 Zn 3 particles precipitated dynamically at the grain boundaries (GBs) could effectively hinder the grain growth during hot extrusion. A weaker texture in DRXed grains was attributed to the coarse-particle stimulated nucleation (PSN) and pinning of the grain boundaries by fine precipitates. The fine DRXed grains, high density of dislocation in the unDRXed region, and fine dense precipitates gave rise to the improved strength of the as-extruded Mg–Zn–Ca–Ce alloy. [ABSTRACT FROM AUTHOR]
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- 2015
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10. Microstructure and strengthening mechanism of carbon nanotubes reinforced magnesium matrix composite.
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Li, C.D., Wang, X.J., Liu, W.Q., Wu, K., Shi, H.L., Ding, C., Hu, X.S., and Zheng, M.Y.
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METAL microstructure , *STRENGTH of materials , *CARBON nanotubes , *MAGNESIUM compounds , *METALLIC composites , *MECHANICAL properties of metals , *METAL extrusion - Abstract
Abstract: Carbon nanotube (CNTs) reinforced Mg matrix composites were successfully fabricated by a novel approach. After hot extrusion, the influence of CNTs on microstructure and mechanical properties of Mg–6Zn matrix was investigated. The results showed that most CNTs distributed uniformly and individually in the composites, and good interfacial bonding was achieved. CNTs significantly refined the grains of Mg–6Zn matrix, and the CNTs evidently improved the ultimate tensile strength (UTS), yield strength (YS) and Young's modulus. Grain refinement, load transfer mechanism and Orowan strengthening mechanism play important roles on the increase of the yield strength. [Copyright &y& Elsevier]
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- 2014
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11. Microstructures and mechanical properties of as-cast and as-extruded Mg-4.50Zn-1.13Ca (wt%) alloys.
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Du, Y.Z., Zheng, M.Y., Xu, C., Qiao, X.G., Wu, K., Liu, X.D., Wang, G.J., and Lv, X.Y.
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MAGNESIUM alloys , *METAL microstructure , *MECHANICAL properties of metals , *MICROFABRICATION , *CRYSTAL grain boundaries , *CRYSTAL texture , *METALS , *METAL castings - Abstract
Abstract: A large Mg-4.50Zn-1.13Ca (wt%) alloy ingot 350mm in diameter and 1730mm long was successfully fabricated by semi-continuous casting. The microstructures and mechanical properties of the as-cast and as-extruded alloys were investigated. The as-cast alloy exhibits uniform chemical composition and microstructure from the centre to the surface of the ingot and mainly consists of α-Mg and Ca2Mg6Zn3. The coarse grains and network-like second phases that are distributed at the grain boundaries result in poor mechanical properties for the as-cast alloy. The mechanical properties of the as-extruded alloys are significantly enhanced. The high yield strengths of the as-extruded alloys mainly result from the fine DRXed grain and the stronger basal texture. [Copyright &y& Elsevier]
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- 2013
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12. Effect of ageing treatment on the microstructure, texture and mechanical properties of extruded Mg–8.2Gd–3.8Y–1Zn–0.4Zr (wt%) alloy
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Chi, Y.Q., Zheng, M.Y., Xu, C., Du, Y.Z., Qiao, X.G., Wu, K., Liu, X.D., Wang, G.J., and Lv, X.Y.
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MAGNESIUM compounds , *MECHANICAL properties of metals , *METAL microstructure , *EFFECT of temperature on metals , *CRYSTAL texture , *METALS , *RECRYSTALLIZATION (Metallurgy) , *EXTRUSION process - Abstract
Abstract: Extruded Mg–8.2Gd–3.8Y–1Zn–0.4Zr (wt%) alloy was subjected to ageing treatment at 200°C. The microstructures, textures and mechanical properties of the as-extruded and peak-aged alloys were investigated. Recrystallization occurred during ageing treatment. A large number of β′ phases were observed in the peak-aged alloy, accompanied with the decrease of the volume fraction of LPSO phases. A basal fiber texture and an unusual texture component with basal planes perpendicular to the extrusion direction were found in the as-extruded alloy, and the basal fiber texture was strengthened after ageing treatment. The peak-aged alloy exhibited a tensile yield strength (TYS), an ultimate tensile strength (UTS) and an elongation to failure of 395MPa, 470MPa and 8%, respectively, at ambient temperature, and 271MPa, 311MPa and 19%, respectively, at 300°C. The superior strength of the peak-aged alloy was mainly attributed to the precipitation of fine β′ phases, the remaining LPSO phases and the texture modification. [Copyright &y& Elsevier]
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- 2013
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13. Microstructure and mechanical properties of Mg–Gd–Y–Zn–Zr alloy sheets processed by combined processes of extrusion, hot rolling and ageing
- Author
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Xu, C., Zheng, M.Y., Xu, S.W., Wu, K., Wang, E.D., Fan, G.H., Kamado, S., Liu, X.D., Wang, G.J., and Lv, X.Y.
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ZIRCONIUM alloys , *METAL microstructure , *MECHANICAL properties of metals , *ROLLING (Metalwork) , *METAL extrusion , *STRAINS & stresses (Mechanics) , *CRYSTAL grain boundaries , *STRENGTH of materials - Abstract
Abstract: The microstructure and mechanical properties of Mg–8.2Gd–3.8Y–1.0Zn–0.4Zr (wt%) alloy sheets produced by combined processes of extrusion, large-strain hot rolling and ageing treatment were investigated. The sheet rolled at 300°C was mainly composed of deformed grains while that rolled at 400°C was fully recrystallized, and the LPSO phase distributed at the grain boundaries in both sheets. The sheet rolled at 300°C and then peak-aged at 200°C exhibits 0.2% proof stress (PS) of 454MPa, ultimate tensile strength (UTS) of 469MPa and elongation to failure of 1.3% at ambient temperature, and 0.2% PS of 413MPa, UTS of 457MPa and elongation to failure of 6.8% at 200°C, respectively. While the sheet rolled at 400°C and peak aged at 200°C had lower 0.2% PS and superior ductility. The improvement of strength is ascribed to the fine β′ phase precipitated within the grains, the LPSO phase and dispersed cuboid Mg–Gd–Y containing phase located at the grain boundaries. [Copyright &y& Elsevier]
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- 2013
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14. Microstructure evolutions of SiCp/AZ91 Mg matrix composites during hot compression
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Wang, X.J., Hu, X.S., Wang, Y.Q., Nie, K.B., Wu, K., and Zheng, M.Y.
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SILICON carbide , *MECHANICAL properties of metals , *METAL microstructure , *METAL castings , *MICROFABRICATION , *STRAINS & stresses (Mechanics) , *PARTICLE size distribution , *CRYSTAL grain boundaries - Abstract
Abstract: 10vol% 10μm SiCp/AZ91 composite fabricated by stir casting was compressed with four temperatures and four strain rates. Compression improved the SiC particle distribution of the composite. Particles segregation was easy to be reduced at higher compressive temperatures. Dynamic recrystallization (DRX) took place in the matrix during hot compression. DRX areas were mainly located near particle aggregations at grain boundaries. Temperatures and strain rates significantly affected the DRX behavior of the matrix, which causes the different microstructures of the composites compressed at different parameters. In addition, temperatures and strain rates also significantly affected the dislocations and twins of the matrix. The secondary twins were observed at higher strain rates. The twins recovered at the higher temperatures and lower strain rates. As temperatures increased, the density and morphology of the dislocations evidently changed. [Copyright &y& Elsevier]
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- 2013
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15. Microstructure and mechanical properties of the Mg/Al multilayer fabricated by accumulative roll bonding (ARB) at ambient temperature
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Chang, H., Zheng, M.Y., Xu, C., Fan, G.D., Brokmeier, H.G., and Wu, K.
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METAL microstructure , *MECHANICAL properties of metals , *MICROFABRICATION , *ROLLING (Metalwork) , *TEMPERATURE effect , *MAGNESIUM compounds , *METALLIC composites , *LAMINATED materials - Abstract
sAbstract: The Mg/Al laminated composites were fabricated by the accumulative roll bonding (ARB) at ambient temperature using the pure magnesium and commercial pure Al sheets. Mg grains were refined after the primary sandwich preparation and then homogenized during the following ARB process while the grain size of Al layer decreased with increasing of the accumulated strains. Both the yield strength and ultimate strength along rolling direction and transverse direction increased gradually while the elongation to failure along both directions decreased with increasing of the ARB cycles. Formation of the Mg17Al12 phase indicated that the ARB process at ambient temperature could lead to a metallurgic bonding of the Mg/Al interface. [Copyright &y& Elsevier]
- Published
- 2012
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16. Effect of particle size on microstructure and mechanical properties of SiCp/AZ91 magnesium matrix composite
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Deng, K.K., Wang, X.J., Wu, Y.W., Hu, X.S., Wu, K., and Gan, W.M.
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PARTICLE size distribution , *METAL microstructure , *MECHANICAL properties of metals , *SILICON carbide , *MAGNESIUM , *METALLIC composites , *METAL extrusion - Abstract
Abstract: In this paper, three kinds of magnesium matrix composites reinforced by SiCp with the sizes of 0.2, 5 and 10μm, respectively, were fabricated by stir casting technology. Then the as-cast ingots were deformed by the combination of forging and extrusion process. Typical microstructures were obtained in the composites reinforced by different particle sizes. For the composites with lower volume fraction of particles (2%), submicron SiCp had significant influence on grain refinement and strengthening effect, which resulted in better mechanical properties of submicron SiCp/AZ91 composite. However, mechanical properties reduced owing to the obvious agglomerated submicron SiC particles as the volume fraction increased to 5% and 10%. On the contrary, for micron SiCp/AZ91 composite, the grain size was refined and the strengthening effect was enhanced with the increasing of volume fraction. Although particle size has no influence on the texture type, it has different effects on weakening the intensity of texture. [Copyright &y& Elsevier]
- Published
- 2012
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17. Influences of extrusion parameters on microstructure and mechanical properties of particulate reinforced magnesium matrix composites
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Wang, X.J., Xu, L., Hu, X.S., Nie, K.B., Deng, K.K., Wu, K., and Zheng, M.Y.
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METALLIC composites , *METAL microstructure , *MECHANICAL properties of metals , *MAGNESIUM , *METAL extrusion , *METAL fractures , *METAL castings - Abstract
Abstract: SiCp/AZ91 composites fabricated by stir casting were extruded at different extrusion temperatures and ratios. Extrusion reduced the necklace-type particle distribution and improved particle distribution of the composites. As extrusion temperatures and ratios increased, particle distribution was improved, and the grain sizes of matrix increased. The mechanical properties of the composites were improved with the increase of extrusion temperatures and ratios. The microstructure evolution of matrix was not the main influential factor of the mechanical properties of the composites. The particle evolution, which included particle redistribution and particle cracking induced by extrusion, significantly affected the mechanical properties of the extruded composites. [Copyright &y& Elsevier]
- Published
- 2011
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18. Effect of Mn addition on microstructure, texture and mechanical properties of Mg–Zn–Ca alloy
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Tong, L.B., Zheng, M.Y., Xu, S.W., Kamado, S., Du, Y.Z., Hu, X.S., Wu, K., Gan, W.M., Brokmeier, H.G., Wang, G.J., and Lv, X.Y.
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MAGNESIUM-calcium-zinc alloys , *MECHANICAL properties of metals , *METAL microstructure , *CRYSTAL texture , *METAL extrusion , *DUCTILITY , *METALS - Abstract
Abstract: The effect of trace Mn addition on the microstructure, texture and mechanical properties of the as-cast and as-extruded Mg–5.25wt.% Zn–0.6wt.% Ca (ZX51) alloys was investigated in this study. Mn addition had a negligible effect on the grain size of the as-cast ZX51 alloy. However, the addition of Mn led to the obvious decrease of grain size in the as-extruded Mg–5.25wt.% Zn–0.6wt.% Ca–0.3wt.% Mn (ZXM510) alloy, because the Mn addition restricted the grain growth during the hot extrusion process. After the addition of Mn, the basal fiber texture with most of {0002} planes parallel to the extrusion direction (ED) was significantly enhanced in the as-extruded ZXM510 alloy. Both tensile yield strength (TYS) and ultimate tensile strength (UTS) were increased in the as-extruded ZXM510 alloy, while the ductility was slightly decreased, which was ascribed to the grain refinement and texture strengthening. [Copyright &y& Elsevier]
- Published
- 2011
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19. Isothermal forging of AZ91 reinforced with 10vol.% silicon carbon particles
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Deng, K.K., Wang, X.J., Gan, W.M., Wu, Y.W., Nie, K.B., Wu, K., Zheng, M.Y., and Brokmeier, H.G.
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FORGING , *MAGNESIUM alloys , *METALLIC composites , *MICROFABRICATION , *INGOTS , *DEFORMATIONS (Mechanics) , *STRENGTH of materials , *METAL microstructure - Abstract
Abstract: In the present study, 10vol.% SiCp/AZ91 magnesium matrix composites are fabricated by stir casting. The as-cast ingots are cut into cylindrical billets, and then forged at 420°C with different deformation amounts (40, 50, 60 and 80%) at a constant RAM speed of 15mm/s. The results illustrate that the addition of SiC particles has significant influence on refining grain size and improving tensile strength of AZ91 matrix, however, weakening basal plane texture. After forging SiCp/AZ91 composites, the intensity of basal plane texture increases as deformation amount increases. The grain size of composite matrix grows up slightly as the deformation amount increased to 60%, and then it was refined obviously as the deformation amount continues to increase to 80%. The smaller deformation amount is propitious to improve particle distribution, while lager deformation amount promotes SiC particle agglomeration. Thus, the tensile strength increases as the deformation amount increases to 50%, however, it decreases as the deformation amount continues to increase to 80%. [Copyright &y& Elsevier]
- Published
- 2011
- Full Text
- View/download PDF
20. Microstructure and mechanical properties of Mg–Zn–Ca alloy processed by equal channel angular pressing
- Author
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Tong, L.B., Zheng, M.Y., Chang, H., Hu, X.S., Wu, K., Xu, S.W., Kamado, S., and Kojima, Y.
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METAL microstructure , *MECHANICAL properties of metals , *MAGNESIUM-calcium-zinc alloys , *DISLOCATIONS in metals , *METAL refining , *RECRYSTALLIZATION (Metallurgy) , *STRAIN hardening , *METAL extrusion - Abstract
Abstract: An ultrafine-grained (UFG) Mg–5.12wt.% Zn–0.32wt.% Ca alloy with an average grain size of 0.7μm was produced by subjecting the as-extruded alloy to equal channel angular pressing (ECAP) for 4 passes at 250°C. The fine secondary phase restricted the dynamic recrystallized (DRXed) grain growth during the ECAP processing, resulting in a remarkable grain refinement. A new texture was formed in the ECAPed Mg alloy with the {0002} plane inclined at an angle of 58° relative to the extrusion direction. The yield stress (YS) was decreased in the as-ECAPed alloy with finer grains, indicating that the texture softening effect was dominant over the strengthening from grain refinement. The ductility of the as-ECAPed alloy was increased to 18.2%. The grain refinement caused an obvious decrease in work hardening rate in the as-ECAPed alloy during tensile deformation at room temperature. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
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