A high-performance Mg-Er-Zn-Zr alloy with low Er/Zn mass ratio

Abstract

The microstructure and properties of a quarternary Mg-8Er-5Zn-0.5Zr (mass fraction, %) alloy with the low Er/Zn mass ratio of 1.60 were investigated. It is found that despite of the low Er/Zn mass ratio, the microstructure of the as-prepared alloy is composed of α-Mg, W phase with face-centered cubic structure and long packed stacking ordered (LPSO) phase. As expected, the extruded and annealed alloy possesses high yield stress (310 MPa) and good elongation (14%) at room temperature. The superior mechanical properties can be interpreted in terms of the promising microstructure characteristic of fine a-Mg recrystallized grains embedded with high-density fine lamellar-shaped LPSO phase and block W phase structure.

Keywords

Mg alloys / extrusion / mechanical properties / microstructure / long packed stacking ordered (LPSO) phase

References

[1] XuD K, HanE H. Effects of icosahedral phase formation on the microstructure and mechanical improvement of Mg alloys: A review [J]. Progress in Natural Science: Materials International, 2012, 22: 364-385

[2] XuD K, LiuL, XuY B, HanE H. The fatigue behavior of I-phase containing as-cast Mg–Zn–Y–Zr alloy [J]. Acta Materialia, 2008, 5: 985-994

[3] LuoZ P, ZhangS Q, TangY L, ZhaoD S. Quasicrystals in as-cast Mg–Zn–RE alloys [J]. Scripta Metall Mater, 1993, 28: 1513-1518

[4] BaeD H, KimS H, KimD H, KimW T. Deformation behavior of Mg–Zn–Y alloys reinforced by icosahedral quasicrystalline particles [J]. Acta Mater, 2002, 50: 2343-2353

[5] NiikuraA, TsaiA P, InoueA, MasumotoA T. Stable Zn–Mg-Rare-Earth face-centered icosahedral alloys with pentagonal dodecahedral solidification structure [J]. Philos Mag Lett, 1994, 69: 351-357

[6] ZhangL, LiuC M, WanY C, YangP W, ShuX. Microstructures and mechanical properties of Mg–10Gd–6Y–2Zn–0.6Zr (wt.%) alloy [J]. Journal of Alloys and Compounds, 2011, 509: 8832-8839

[7] ShaoX H, YangZ Q, MaX L. Strengthening and toughening mechanisms in Mg–Zn–Y alloy with a long period stacking ordered structure [J]. Acta Materialia, 2010, 14: 4760-4770

[8] LiuH, XueF, BaiJ, SunY S. Effect of heat treatments on the microstructure and mechanical properties of an extruded Mg_95.5Y₃Zn_1.5 alloy [J]. Materials Science and Engineering A, 2013, 585: 261-267

[9] LiJ H, DuW B, LiS B, WangZ H. Icosahedral quasicrystalline phase in an as-cast Mg-Zn-Er alloy [J]. Rare Metals, 2009, 28: 297-301

[10] ZhangY, ZhengX, LiuL, ZhouH, LiQ, ZhuY. Microstructure evolution of Mg-4.3Zn-0.7Y-0.6Zr alloy during solution heat treatment [J]. Materials Science and Engineering A, 2004, 373: 320-325

[11] YangW-p, GuoX-feng. High strength magnesium alloy with α-Mg and W phase processed by hot extrusion [J]. Transactions of Nonferrous Metals Society of China, 2011, 21(11): 2358-2364

[12] LiH, DuW B, LiS B, WangZ H. Effect of Zr/Er weight ratio phase formation and mechanical properties of as-cast Mg-Zn-Er alloys [J]. Materials and Design, 2012, 35: 259-265

[13] WangQ F, LiuK, WangZ H, LiS B, DuW B. Microstructure, texture and mechanical properties of as-extruded Mg-Zn-Er alloys containing W phase [J]. Journal of Alloys and Compounds, 2014, 602: 32-39

[14] WangJ F, SongP F, ZhouZ E, HuangX F, PanF S. Influence of the morphology of long-period stacking ordered phase on the mechanical properties of as-extruded Mg–5Zn–5Y–0.6Zr magnesium alloy [J]. Materials Science & Engineering A, 2012, 556: 68-75

[15] ZhangJ S, ZhangW B, RuanX Q, BianL P, ChengW L, WangH X, XuC X. Effect of zirconium on the microstructure and mechanical properties of long period stacking ordered Mg₉₆Gd₃Zn₁ alloy [J]. Materials Science and Engineering A, 2013, 560: 847-850

[16] DuX H, HongM, DuanG S, WangD P, WuB L, ZhangY D, EslingC. Effect of V on the microstructure and mechanical properties of Mg-10Er-2Cu alloy with a long period stacking ordered structure [J]. Materials Letters, 2014, 122: 312-314

[17] GongX, KangS B, ChoJ H, LiS. Effect of annealing on microstructure and mechanical properties of ZK60 magnesium alloy sheets processed by twin-roll cast and differential speed rolling [J]. Materials Characterization, 2014, 97: 183-188

[18] GongX, KangS B, LiS, ChoJ H. Enhanced plasticity of twin-roll cast ZK60 magnesium alloy through differential speed rolling [J]. Materials and Design, 2009, 30(9): 3345-3350

[19] LiuK, ZhangJ, LuH, TangD, RokhlinLL. Effect of the long periodic stacking structure and W-phase on the microstructures and mechanical properties of the Mg–8Gd–xZn–0.4Zr alloys [J]. Materials and Design, 2010, 31: 210-219

[20] HouX, PengQ, CaoZ, XuS, KamadoS, WangL. Structure and mechanical properties of extruded Mg–Gd based alloy sheet [J]. Materials Science and Engineering A, 2009, 520: 162-167

[21] RokhlinL LMagnesium alloys containing rare earth metals–structure and properties [M], 2003LondonTaylor & Francis210-223

[22] LiuK, RokhlinL L, ElkinF M, TangD, MengJ. Effect of ageing treatment on the microstructures and mechanical properties of the extruded Mg–7Y–4Gd–1.5Zn–0.4Zr alloy [J]. Materials Science and Engineering A, 2010, 527: 828-834

[23] LiuX B, ChenR S, HanE H. Effects of ageing treatment on microstructures and properties of Mg–Gd–Y–Zr alloys with and without Zn additions [J]. Journal of Alloys and Compounds, 2008, 465: 232-238

[24] ZhengL, LiuC, WanY, YangP, ShuX. Microstructures and mechanical properties of Mg–10Gd–6Y–2Zn–0.6Zr (wt.%) alloy [J]. Journal of Alloys and Compounds, 2011, 509: 8832-8839