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Development of low-alloyed and rare-earth-free magnesium alloys having ultra-high strength
Pan, HC; Qin, GW; Huang, YM; Ren, YP; Sha, XC; Han, XD; Liu, ZQ; Li, CF; Wu, XL; Chen, HW; He, C; Chai, LJ; Wang, YZ; Nie, JF; Qin, GW (reprint author), Northeastern Univ, Minist Educ, Sch Mat Sci & Engn, Key Lab Anisotropy & Texture Mat, Shenyang 110819, Liaoning, Peoples R China.; Nie, JF (reprint author), Chongqing Univ, Sch Mat Sci & Engn, Chongqing 400044, Peoples R China.; Wang, YZ (reprint author), Ohio State Univ, Dept Mat Sci & Engn, 2041 N Coll Rd, Columbus, OH 43210 USA.
2018-05-01
Source PublicationACTA MATERIALIA
ISSN1359-6454
Volume149Pages:350-363
AbstractDeveloping ultra-high strength in rare-earth-free Mg alloys using conventional extrusion process is a great challenge. What is even more difficult is to achieve such a goal at a lower processing cost. In this work, we report a novel low-alloyed Mg-2Sn-2Ca alloy (in wt. %) that exhibits tunable ultra-high tensile yield strength (360-440 MPa) depending on extrusion parameters. More importantly, there is little drop in mechanical properties of this alloy even when it is extruded at a speed several times higher than those used in the reported high strength Mg alloys. Examination of as-extruded microstructures of this Ca-containing Mg alloy reveals that the ultra-high strength is mainly associated with the presence of surprisingly submicron matrix grains (down to similar to 0.32 mu m). The results suggest that the Ca addition promotes accumulations of the pyramidal dislocations, which eventually transform into the low angular grain boundaries (LAGBs). The high number density of LAGBs separate the alpha-Mg matrix via either discontinuous dynamic recrystallization (DDRX) mechanism in the early stage or the continuous dynamic recrystallization (CDRX) mechanism in the later stage of extrusion, which effectively enhances the nucleation rates of the DRXed grains. More importantly, large amount of Ca segregation along LAGBs, accompanied with dynamically precipitated Mg2Ca nano-phases, are detected in the present non-severely deformed samples. It is the combination of solute segregations and numerous Mg2Ca nano-precipitates that contributes to the formation of the ultra-fine grains via pinning mechanism. The ultrafine grains size, Ca enrichment in most LAGBs, and residual Mg2Ca nano-precipitates would in turn contribute significantly to the enhancement of the yield strength of the as-extruded Mg-2Sn-2Ca (wt.%) alloy. The low content of alloying elements and the fast one-step extrusion process render the present alloys low-cost and thus have great potential in large-scale industry applications. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.; Developing ultra-high strength in rare-earth-free Mg alloys using conventional extrusion process is a great challenge. What is even more difficult is to achieve such a goal at a lower processing cost. In this work, we report a novel low-alloyed Mg-2Sn-2Ca alloy (in wt. %) that exhibits tunable ultra-high tensile yield strength (360-440 MPa) depending on extrusion parameters. More importantly, there is little drop in mechanical properties of this alloy even when it is extruded at a speed several times higher than those used in the reported high strength Mg alloys. Examination of as-extruded microstructures of this Ca-containing Mg alloy reveals that the ultra-high strength is mainly associated with the presence of surprisingly submicron matrix grains (down to similar to 0.32 mu m). The results suggest that the Ca addition promotes accumulations of the pyramidal dislocations, which eventually transform into the low angular grain boundaries (LAGBs). The high number density of LAGBs separate the alpha-Mg matrix via either discontinuous dynamic recrystallization (DDRX) mechanism in the early stage or the continuous dynamic recrystallization (CDRX) mechanism in the later stage of extrusion, which effectively enhances the nucleation rates of the DRXed grains. More importantly, large amount of Ca segregation along LAGBs, accompanied with dynamically precipitated Mg2Ca nano-phases, are detected in the present non-severely deformed samples. It is the combination of solute segregations and numerous Mg2Ca nano-precipitates that contributes to the formation of the ultra-fine grains via pinning mechanism. The ultrafine grains size, Ca enrichment in most LAGBs, and residual Mg2Ca nano-precipitates would in turn contribute significantly to the enhancement of the yield strength of the as-extruded Mg-2Sn-2Ca (wt.%) alloy. The low content of alloying elements and the fast one-step extrusion process render the present alloys low-cost and thus have great potential in large-scale industry applications. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
description.department[pan, hucheng ; qin, gaowu ; huang, yunmiao ; ren, yuping] northeastern univ, minist educ, sch mat sci & engn, key lab anisotropy & texture mat, shenyang 110819, liaoning, peoples r china ; [sha, xuechao ; han, xiaodong] beijing univ technol, inst microstruct & properties adv mat, beijing 100124, peoples r china ; [liu, zhi-quan ; li, caifu] chinese acad sci, inst met res, shenyang 110016, liaoning, peoples r china ; [wu, xiaolei] chinese acad sci, inst mech, state key lab nonlinear mech, beijing 100190, peoples r china ; [chen, houwen ; he, cong ; nie, jian-feng] chongqing univ, sch mat sci & engn, chongqing 400044, peoples r china ; [chai, linjiang] chongqing univ thchnol, coll mat sci & engn, chongqing 400054, peoples r china ; [wang, yunzhi] ohio state univ, dept mat sci & engn, 2041 n coll rd, columbus, oh 43210 usa ; [nie, jian-feng] monash univ, dept mat sci & engn, clayton, vic 3800, australia
KeywordSlow-speed Extrusion Zn-zr Alloy Ca-mn Alloy Mechanical-properties Low-temperature Grain-refinement Microstructure Evolution Mg-3al-1zn Alloy Prismatic-slip Pure Magnesium
Subject AreaMaterials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering
Funding OrganizationNational Key Research and Development Program of China [2016YFB0701200]; National Natural Science Foundation of China [51525101, U1610253, 51371046, 51501032, 51131009]
Indexed BySCI
Language英语
Document Type期刊论文
Identifierhttp://ir.imr.ac.cn/handle/321006/79327
Collection中国科学院金属研究所
Corresponding AuthorQin, GW (reprint author), Northeastern Univ, Minist Educ, Sch Mat Sci & Engn, Key Lab Anisotropy & Texture Mat, Shenyang 110819, Liaoning, Peoples R China.; Nie, JF (reprint author), Chongqing Univ, Sch Mat Sci & Engn, Chongqing 400044, Peoples R China.; Wang, YZ (reprint author), Ohio State Univ, Dept Mat Sci & Engn, 2041 N Coll Rd, Columbus, OH 43210 USA.
Recommended Citation
GB/T 7714
Pan, HC,Qin, GW,Huang, YM,et al. Development of low-alloyed and rare-earth-free magnesium alloys having ultra-high strength[J]. ACTA MATERIALIA,2018,149:350-363.
APA Pan, HC.,Qin, GW.,Huang, YM.,Ren, YP.,Sha, XC.,...&Wang, YZ .(2018).Development of low-alloyed and rare-earth-free magnesium alloys having ultra-high strength.ACTA MATERIALIA,149,350-363.
MLA Pan, HC,et al."Development of low-alloyed and rare-earth-free magnesium alloys having ultra-high strength".ACTA MATERIALIA 149(2018):350-363.
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