TY - JOUR

T1 - Microstructures and mechanical properties of a hot-extruded Mg−8Gd−3Yb−1.2Zn−0.5Zr (wt%) alloy

AU - Li, Baishun

AU - Guan, Kai

AU - Yang, Qiang

AU - Niu, Xiaodong

AU - Zhang, Dongdong

AU - Lv, Shuhui

AU - Meng, Fanzhi

AU - Huang, Yuanding

AU - Hort, Norbert

AU - Meng, Jian

PY - 2019/3/5

Y1 - 2019/3/5

N2 - Microstructures and mechanical properties of a Mg−8Gd−3Yb−1.2Zn−0.5Zr (wt%) alloy have been investigated. The dominant intermetallic phases in the as-cast sample are Mg5RE (RE = Gd,Yb) phase, 14H-type long-period stacking ordered (LPSO) phase, and Mg2Zn2RE (W) phase and ordered Mg12RE phase. Furthermore, the ordered Mg12RE phase generally coexists with the W phase following an orientation relationship as [01¯1]w//[2¯30]Mg12RE, and (1¯11)w//(001)Mg12RE. After extrusion, the microstructure is consisted of un-recrystallized regions along with a small part of fine dynamically recrystallized (DRXed) regions. Simultaneously, the coarse Mg5RE, W and Mg12RE particles were disintegrated and mainly distribute at extrusion stringers while the fine LPSO plates mainly distribute in un-recrystallized regions. Moreover, amounts of nanoscale Mg5RE particles were dynamically precipitated in DXRed regions. Then, the as-extruded Mg−8Gd−3Yb−1.2Zn−0.5Zr alloy exhibits clearly higher strength than the classic rare-earth-containing magnesium alloys with comparative or even much higher rare earth content at both room temperature and high temperatures. The dominant strengthening mechanism was finally revealed as precipitation/dispersion strengthening.

AB - Microstructures and mechanical properties of a Mg−8Gd−3Yb−1.2Zn−0.5Zr (wt%) alloy have been investigated. The dominant intermetallic phases in the as-cast sample are Mg5RE (RE = Gd,Yb) phase, 14H-type long-period stacking ordered (LPSO) phase, and Mg2Zn2RE (W) phase and ordered Mg12RE phase. Furthermore, the ordered Mg12RE phase generally coexists with the W phase following an orientation relationship as [01¯1]w//[2¯30]Mg12RE, and (1¯11)w//(001)Mg12RE. After extrusion, the microstructure is consisted of un-recrystallized regions along with a small part of fine dynamically recrystallized (DRXed) regions. Simultaneously, the coarse Mg5RE, W and Mg12RE particles were disintegrated and mainly distribute at extrusion stringers while the fine LPSO plates mainly distribute in un-recrystallized regions. Moreover, amounts of nanoscale Mg5RE particles were dynamically precipitated in DXRed regions. Then, the as-extruded Mg−8Gd−3Yb−1.2Zn−0.5Zr alloy exhibits clearly higher strength than the classic rare-earth-containing magnesium alloys with comparative or even much higher rare earth content at both room temperature and high temperatures. The dominant strengthening mechanism was finally revealed as precipitation/dispersion strengthening.

KW - Intermetallic phase

KW - Magnesium alloy

KW - Mechanical properties

KW - Strengthening mechanism

KW - Transmission electron microscopy (TEM)

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=85055752165&partnerID=8YFLogxK

U2 - 10.1016/j.jallcom.2018.10.322

DO - 10.1016/j.jallcom.2018.10.322

M3 - Journal articles

AN - SCOPUS:85055752165

VL - 776

SP - 666

EP - 678

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

SN - 0925-8388

ER -