The microstructure and mechanical properties of as-cast Mg–4Y/Nd

Abstract

Optical microscopy, scanning electron microscopy, X-ray diffraction and tensile testing were performed to investigate the microstructure and mechanical properties of as-cast Mg–4Y/Nd–2Zn alloys. The results show that the secondary dendritic arm spacing for the Mg–4Y–2Zn alloy is smaller than that for the Mg–4Nd–2Zn alloy, and that X-Mg₁₂YZn or W-Mg₃Zn₃Nd₂ form in Mg–4Y/Nd–2Zn alloys. The lamellar X phase distributes at the grain boundary, pointing into the grains, whereas the rod-like W phase preferentially segregates at the triangle junction of the grain boundary. The greater grain boundary strengthening effect and the smaller fragmentation effect of the brittle eutectic phases leads to the as-cast Mg–4Y–2Zn alloy having better comprehensive mechanical properties. The fracture mechanism for as-cast Mg–4Y/Nd–2Zn alloys is quasi-cleavage fracture.

Keywords

Mg–4Y/Nd–2Zn alloys X phase W phase microstructure mechanical properties

Introduction

As the lightest metal structure materials, magnesium alloys have the characteristics of low density, high specific strength, perfect cutting performance, excellent thermal conductivity and good electromagnetic shielding performance. So, it has been widely used as structural material in aviation, aerospace, automobile industry and other industries [1 –3]. Unfortunately, relatively low strength, ductility and poor corrosion resistance of magnesium alloys have limited its application in the engineering field [4,5]. To improve the mechanical properties of magnesium alloys, lots of work has been done in the development of new magnesium alloys. It has been demonstrated that rare earth elements are the most effective elements to improve the strength properties of magnesium alloys, and the Mg–RE system is an ideal candidate for developing new magnesium alloys with high performance (RE represents rare earth elements). Most of the rare earth elements have a large solid solubility in magnesium; Mg–RE binary alloys have a significant effect of solid solution strengthening, which can effectively improve the mechanical properties of magnesium alloys at room temperature and elevated temperature. In addition, rare earth elements have significant ageing strengthening effect, which can greatly improve the high-temperature strength and creep resistance of magnesium alloys [6 –8].

Y or Nd is one of the light rare earth elements with high solubility in an Mg matrix, and thus offers great potentiality for age-hardening. The precipitation process of prime α-Mg supersaturated solid solution in binary Mg–Y/Nd alloys is as follows: G.P. zones→β′′ (DO₁₉) metastable phase→β′ metastable phase→β equilibrium phase [9 –11]. The formation of the age-hardening phases is beneficial to improve the strength of magnesium alloys. The addition of other alloying elements to Mg–RE binary alloys, such as Al, Zn and Zr, results in great improvement in the mechanical properties of magnesium alloys. Zn is one of the most commonly used alloying element in magnesium alloys, and the maximum solid solubility of Zn in an Mg matrix is 6.2% at eutectic temperature (all of the percentages refer to weight percentage if not specific statement), and the solid solubility decreases with the decreasing of temperature, which produces significant solid solution strengthening and ageing strengthening in the Mg matrix. In addition, Zn can also reduce the corrosion of Fe, Cu and other impurity elements in magnesium [12 –15].

Up to now, most researches have focused on microstructure and mechanical properties of Mg–Zn–RE alloys. There are three kinds of ternary phases in the Mg–Zn–Y system alloys, such as X phase (Mg₁₂ZnY, long period stacking ordered (LPSO) structure), I phase (Mg₃Zn₆Y, icosahedral quasicrystal structure, quasi-periodically ordered) and W phase (Mg₃Zn₃Y₂, cubic structure). The formation and quantity of the three phases are related to the Zn/Y atomic ratio [16 –23]. T phase (Mg₅₆Nd₁₅Zn₂₉, c-base-centred-orthorhombic structure) and W phase (Mg₃Zn₃Nd₂, face-centred cubic structure) exist in Mg–Zn–Nd system alloys. The lattice constant of W-Mg₃Zn₃Nd₂ is larger than that of the W-Mg₃Zn₃Y₂ phase, because the atomic radius of Nd is larger than that of the Y atom, so the lattice constant of the W phase increases when Y is replaced by Nd [24 –27]. Up to now, there are a few researches that focus on Mg–RE–Zn alloys. In this paper, the microstructure, phase composition and mechanical properties of as-cast Mg–4Y/Nd–2Zn alloys have been investigated.

Experimental

Commercial pure Mg, pure Zn, Mg–20Y master alloy and Mg–20Nd master alloy were used as raw materials to prepare the Mg–4Y/Nd–2Zn alloys. The chemical compositions of experimental alloys are given in Table 1. Mg-4Y/Nd-2Zn alloys were melted in an electrical resistance furnace under the protective atmosphere consisting of Ar and SF₆ with the mixing ratio of V_SF6_: V_Ar = 1:100. The melt was held at 720°C for 20 min and then poured into a copper mould with a dimension of 200 mm × 150 mm × 25 mm.

Table 1

Chemical composition of the experiment alloys (wt-%).

Alloy	Y	Nd	Zn	Mg
Mg–4Y–2Zn	4	0	2	Bal.
Mg–4Nd–2Zn	0	4	2	Bal.

The tensile tests were performed by a CSS-2202 universal testing machine at room temperature, and the gauge dimensions of platy tensile test specimens were 15 mm×4 mm×2 mm. Hardness tests were performed using a 100 N load and loading time of 15 s. Metallographic specimens were finished and polished by a standard metallographic technique and then etched with 3 vol.-% nital. The microstructures of the alloys were observed using a MR5000 optical microscopy, and the average grain size of the alloys was measured quantitatively by the average linear intercept method. Phase identification of the alloys was examined by a Bruker D8 Advance X-ray diffraction (XRD). The phase distribution and fractography of the alloys were characterised by a Hitachi S-4800 scanning electron microscope (SEM) equipped with energy-dispersive spectroscopy (EDS). In addition, the solidification process of as-cast Mg–4Y/Nd–2Zn alloys was analysed by a STA 449 F1 differential scanning calorimeter (DSC).

Results and discussion

Microstructure

The optical micrographs of as-cast Mg–4Y/Nd–2Zn alloys are shown in Figure 1. It can be found that the secondary phases distribute in grain boundaries, and experimental alloys show a microstructure with typical casting dendrites, which is characterised by strong segregation of the alloying elements. The secondary dendritic arm spacings of the Mg–4Y–2Zn and Mg–4Nd–2Zn are 25–28 µm and 36–40 µm, respectively. The XRD analysis results of as-cast Mg–4Y/Nd–2Zn alloys are given in Figure 2. Mg–4Y–2Zn alloy contains α-Mg and an X-Mg₁₂YZn phase with a long period stacking order (LPSO) structure [10,16 –18,28,29], while the Mg–4Nd–2Zn alloy contains α-Mg and the W-Mg₃Zn₃Nd₂ phase with a face-centre cubic structure [25,26].

Figure 1

Microstructure of as-cast Mg–4Y/Nd–2Zn alloys: (a) Mg–4Y–2Zn and (b) Mg–4Nd–2Zn.

Figure 2

XRD patterns of as-cast Mg–4Y/Nd–2Zn alloys.

Figure 3 shows the SEM micrographs of as-cast Mg–4Y/Nd–2Zn alloys, and the element distribution of as-cast Mg–4Y/Nd–2Zn alloys is shown in Figure 4. As observed, the lamellar second phase that distributes at the grain boundaries pointed into the grains in the as-cast Mg–4Y–2Zn alloy is X-Mg₁₂YZn phase, whereas the second phase along the grain boundaries for the as-cast Mg–4Nd–2Zn alloy is W-Mg₃Zn₃Y₂phase, most of which is in the form of parallel rod-like at the triple junctions of grain boundaries [30,31]. Although most of the Y, Nd and Zn atoms are concentrated at grain boundaries, there are still some Y, Nd and Zn atoms that dissolve in the matrix, especially Y atoms.

Figure 3

SEM images of as-cast Mg–4Y/Nd–2Zn alloys: (a) Mg–4Y–2Zn and (b) Mg–4Nd–2Zn.

Figure 4

Elements’ distribution of as-cast Mg–4Y/Nd–2Zn alloys by EDS analysis: (a) SEM image of Mg–4Y–2Zn, (b) SEM image of Mg–4Nd–2Zn, (c) Y distribution of the Mg–4Y–2Zn alloy, (d) Nd distribution of the Mg–4Nd–2Zn alloy, (e) Zn distribution of the Mg–4Y–2Zn alloy and (f) Zn distribution of the Mg–4Nd–2Zn alloy.

To further verify the formation of the Mg–Y/Nd–Zn ternary phases, the solidification processes of the Mg–Y/Nd–Zn alloys have been discussed based on the results of DSC, and the DSC results of as-cast Mg–4Y/Nd–2Zn alloys are shown in Figure 5. Two experimental alloys have a large endothermic peak at about 633–639°C, which corresponds to the melting temperature of the primary α-Mg phase. The Mg–4Y–2Zn alloy has another endothermic peak at 535°C besides that at 639°C (Figure 5a), the phases in the as-cast Mg–4Y–2Zn alloy are X phase and α-Mg, and the X phase originates from the ternary eutectic reaction of L→α-Mg+X at the temperature of 535°C [31,33,34]. For the Mg–4Nd–2Zn alloy, it has another endothermic peak at 512°C besides that at 633°C (Figure 5b), which correspond to the melting point of the W phase [25,26], and the W phase also originates from the ternary eutectic reaction of L→α-Mg+W. Therefore, the melting point of the ternary eutectic phase of the Mg–4Y–2Zn alloy is 23°C higher than that of the Mg–4Nd–2Zn alloy.

Figure 5

DSC curves of as-cast Mg–4Y/Nd–2Zn alloys: (a) Mg–4Y–2Zn and (b) Mg–4Nd–2Zn.

Mechanical properties

The mechanical properties of experimental alloys at room temperature are shown in Table 2. The ultimate tensile strength, elongation and hardness of the Mg–4Y–2Zn alloy are 169 MPa, 9.9% and 68.3 HV, respectively. The ultimate tensile strength, elongation and hardness of the Mg–4Nd–2Zn alloy are 142 MPa, 7.6% and 52.9 HV, respectively. Compared with the Mg–4Nd–2Zn alloy, the Mg–4Y–2Zn alloy has better mechanical properties, and its tensile strength, elongation and hardness are increased by 19, 30 and 29%.

Table 2

Mechanical properties of as-cast Mg–4Y/Nd–2Zn alloys.

Alloy	UTS/MPa	Elongation/%	Hardness/HV
Mg–4Y–2Zn	169	9.9	68.3
Mg–4Nd–2Zn	142	7.6	52.9

Table 3 shows the scanning results of the content of solid solution elements in the α-Mg matrix for the A and B areas of Figure 4. It can be seen that the average contents of Y and Nd in the magnesium matrix are only 0.67 and 0.40 at.-%, respectively. It also reconfirms that most of the Y and Nd atoms are present in the eutectic phase, with only a small amount of Y and Nd atoms dissolving in the matrix. As the solution strengthening effect is increased with the content of the solution alloying elements, the content of Y in the matrix is higher than that of Nd in the matrix. In addition, Zinc is a major element in the solution strengthening of the magnesium alloy, and the content of Zn in the matrix of the Mg–4Y–2Zn alloy is significantly higher than that of the Mg–4Y–2Zn alloy. Therefore, the solution strengthening effect of the Mg–4Y–2Zn alloy is better than that of the Mg–4Nd–2Zn alloy.

Table 3

The content of solid solution elements in the α-Mg matrix (at.-%).

Alloy	Y	Nd	Zn	Mg
Mg–4Y–2Zn	0.67	0	1.53	97.80
Mg–4Nd–2Zn	0	0.40	1.31	98.29

Ternary phases have been formed in Mg–4Y/Nd–2Zn alloys, and their quantity, morphology and distribution have a significant effect on the mechanical properties of the alloys. The eutectic phase distributed along the grain boundary led to a grain boundary strengthening effect [32], there is a good interface matching between the X-Mg₁₂YZn phase with long period stacking structure and the Mg matrix in Mg–4Y–2Zn alloys, the Vickers hardness (137 ± 3.4 HV) of the X-Mg₁₂YZn phase is much higher than that of pure magnesium (31.3 ± 2.2 HV) and the LPSO structure can more effectively prevent the dislocation movement [28,35,36], while the W-Mg₃Zn₃Nd₂ phase with face-centred cubic structure is inconsistent with the hexagonal structure of the α-Mg matrix in Mg–4Nd–2Zn, and has a weak grain boundary strengthening effect; therefore, the room temperature strength and plasticity of the as-cast Mg–4Y–2Zn alloy are better than that of the as-cast Mg–4Nd–2Zn alloy. On the other hand, the greater the amount of solid solution of Zn in the matrix, the lesser the amount of eutectic phase formed from the eutectic melt at the end of the solidification process. The content of Zn in the matrix of the as-cast Mg–4Y–2Zn alloy is much higher than that of the as-cast Mg–4Y–2Zn alloy, the amount of eutectic phase in the as-cast Mg–4Y–2Zn alloy will be smaller. Furthermore, the lamellar X–Mg₁₂YZn phase at the grain boundaries in the as-cast Mg–4Y–2Zn alloy is pointed into the grains, whereas the W-Mg₃Zn₃Y₂ phase in the as-cast Mg–4Nd–2Zn alloy is along the grain boundaries (Figure 4); therefore, the fragmentation effect of the brittle eutectic phases in the as-cast Mg–4Y–2Zn alloy will be greatly reduced, and the as-cast Mg–4Y–2Zn alloy has better mechanical properties.

Rare earths play an important role in the grain refinement. When the alloy is solidified in the way of dendrite, the primary dendrite arm spacing d_l can be expressed as follows [37]: (1) where L is the latent heat of crystallisation, D_L is the diffusion coefficient of solute in the liquid phase, Γ is the Gibbs–Thomson coefficient, k₀ is the equilibrium distribution coefficient, ΔT₀ is the crystallisation temperature interval, T_m is the melting point of the base metal, G_L is the liquid phase temperature gradient at the front of the solid/liquid interface and V is the solidification velocity. The broad crystallisation temperature interval ΔT₀ will increase the primary dendrite arm spacing d_l, the DSC results show that the crystallisation temperature interval of the Mg–4Nd–2Zn alloy is wider than that of the Mg–4Y–2Zn alloy, the primary dendrite arm spacing of the Mg–4Y–2Zn alloy is smaller. It has been proved that the strength of polycrystal increases with the grain refinement; the relation between the yield strength (σ_s) and the average grain size (d) can be represented by the Hall–Petch formula [38]: (2)

The grain size of the as-cast Mg–4Y–2Zn alloy is smaller than that of the as-cast Mg–4Nd–2Zn alloy (Figure 1); therefore, the as-cast Mg–4Y–2Zn alloy has better mechanical properties.

The typical fracture surface images of as-cast Mg–4Y/Nd–2Zn alloys are shown in Figure 6. The fracture mechanisms of magnesium alloys are mainly cleavage fracture and quasi-cleavage fracture. It can be seen that the fracture surfaces of as-cast Mg–4Y/Nd–2Zn alloys have tearing edges, cleavage faces and small dimples. Therefore, the fracture mechanisms of as-cast Mg–4Y/Nd–2Zn alloys are quasi-cleavage fracture. The fracture tearing edges of the as-cast Mg–4Y–2Zn alloy are more developed, and the dimensions and quantity of the dimples are comparatively large and deep; so its plasticity is comparatively good.

Figure 6

Fractographs of as-cast Mg–4Y/Nd–2Zn alloys: (a) Mg–4Y–2Zn and (b) Mg–4Nd–2Zn.

Conclusions

The ternary phases of the as-cast Mg–4Y–2Zn and Mg–4Nd–2Zn alloys are the X-Mg₁₂YZn phase and the W-Mg₃Zn₃Nd₂ phase, respectively. The lamellar X phase distributes at the grain boundary pointed into the grains, whereas the rod-like W phase is preferentially segregated in the triangle junction of the grain boundary. The microstructures of the as-cast alloys show typical casting dendrites, and the secondary dendritic arm spacings of the Mg–4Y–2Zn and Mg–4Nd–2Zn are 25–28 µm and 36–40 µm, respectively. The melting point of the ternary eutectic phase of the Mg–4Y–2Zn alloy is 23°C higher than that of the Mg–4Nd–2Zn alloy.

The greater grain boundary strengthening effect and the smaller fragmentation effect of the brittle eutectic phases make the as-cast Mg–4Y–2Zn alloy have better comprehensive mechanical properties. The tensile strength, elongation and hardness of the Mg–4Y–2Zn alloy are 169 MPa, 9.9% and 68.3 HV, respectively. They are increased by 19, 30 and 29%, respectively, compared with those of the Mg–4Nd–2Zn alloy.

The fracture mechanism of as-cast Mg–4Y/Nd–2Zn alloys is quasi-cleavage fracture, and the as-cast Mg–4Y–2Zn alloy has good plasticity.

Footnotes

Disclosure statement

No potential conflict of interest was reported by the authors.

References

Chen

, Geng

, Pan

FS.

Research progress in magnesium alloys as functional materials. Rare Metal Mat Eng. 2016;45(9):2269–2274. doi: 10.1016/S1875-5372(17)30015-2

Luo

AA.

Magnesium casting technology for structural applications. J Mag Alloy. 2013;1(1):2–22. doi: 10.1016/j.jma.2013.02.002

Pan

, Pan

, Wang

, Peng

, High conductivity and high strength Mg–Zn–Cu alloy. Mater Sci Technol 2014;30:759–764. doi: 10.1179/1743284713Y.0000000400

Hirsch

, Al-Samman

Superior light metals by texture engineering: optimized aluminum and magnesium alloys for automotive applications. Acta Mater. 2013;61(3):818–843. doi: 10.1016/j.actamat.2012.10.044

Bettles

, Gibson

MA.

Microstructural design for enhanced elevated temperature properties in sand-castable magnesium alloys. Adv Eng Mater. 2003;5(12):859–865. doi: 10.1002/adem.200310103

Yin

, Liu

, Effects of Al addition on the microstructure and mechanical properties of Mg–4Y alloys. Mater Sci Technol. 2017;33(18):2188–2196. doi: 10.1080/02670836.2017.1353664

Arrabal

, Mingo

, Pardo

, Role of alloyed Nd in the microstructure and atmospheric corrosion of as-cast magnesium alloy AZ91. Corros Sci. 2015;97:38–48. doi: 10.1016/j.corsci.2015.04.004

, Chiu

, Jones

IP.

Effect of Gd on the microstructure of as-cast Mg-4.2Zn-0.8Y (at.%) alloys. J Alloy Compd. 2016;661:455–460. doi: 10.1016/j.jallcom.2015.11.209

, Liu

, Wang

, Effect of Y content on microstructure and mechanical properties of Mg–2.4Nd–0.2Zn–0.4Zr alloys. Mater Sci Technol. 2013;29(2):148–155. doi: 10.1179/1743284712Y.0000000149

10.

Zheng

, Dong

, Zeng

, Precipitation and its effect on the mechanical properties of a cast Mg–Gd–Nd–Zr alloy. Mater Sci Eng. 2008;489(1):44–54. doi: 10.1016/j.msea.2007.11.080

11.

Nie

, Muddle

BC.

Characterisation of strengthening precipitate phases in a Mg–Y–Nd alloy. Acta Mater. 2000;48(8):1691–1703. doi: 10.1016/S1359-6454(00)00013-6

12.

Solomon

ELS

, Chan

, Chen

, Aging behavior of Mg alloys containing Nd and Y. In: Solanki

, Orlov

, Singh

, editors. Magnesium Technology. Germany: Springer; 2017. p. 349–352. https://doi.org/10.1007/978-3-319-52392-7_50.

13.

Nie

, Wilson

, Zhu

, Solute clusters and GP zones in binary Mg–RE alloys. Acta Mater. 2016;106:260–271. doi: 10.1016/j.actamat.2015.12.047

14.

Issa

, Saal

, Wolverton

Formation of high-strength β′ precipitates in Mg–RE alloys: The role of the Mg/β′′ interfacial instability. Acta Mater. 2015;83:75–83. doi: 10.1016/j.actamat.2014.09.024

15.

, Liu

, Chen

, Effects of Zn content on microstructures and mechanical properties of as cast Mg–Zn–Y–Zr alloys. Mater Sci Technol. 2013;29(4):480–486. doi: 10.1179/1743284712Y.0000000165

16.

Tang

, Li

, Tang

, Effect of long period stacking ordered structure on mechanical and damping properties of as-cast Mg–Zn–Y–Zr alloy. Mater Sci Eng. 2015;640:287–294. doi: 10.1016/j.msea.2015.06.004

17.

Zhang

, Liu

, Hu

, Microstructures, mechanical properties and corrosion behaviors of Mg–Y–Zn–Zr alloys with specific Y/Zn mole ratios. J Alloy Compd. 2015;624:116–125. doi: 10.1016/j.jallcom.2014.10.177

18.

, Teng

, Lou

, Microstructure and mechanical properties of Mg-Zn-Y alloy containing LPSO phase and I-phase. Mater Res Express. 2017;4(8):086502. doi: 10.1088/2053-1591/aa7f8f

19.

Liu

, Zhang

, Mao

, Effects of Y on hot tearing formation mechanism of Mg–Zn–Y–Zr alloys. Mater Sci Technol. 2014;30(10):1214–1222. doi: 10.1179/1743284713Y.0000000437

20.

Yang

M-b

, Wu

D-y

, Hou

M-d

, As-cast microstructures and mechanical properties of Mg–4Zn–xY–1Ca (x= 1.0, 1.5, 2.0, 3.0) magnesium alloys. Trans Nonferr Metal Soc. 2015;25(3):721–731. doi: 10.1016/S1003-6326(15)63657-3

21.

Chen

, Lin

, Zeng

, Effects of yttrium and zinc addition on the microstructure and mechanical properties of Mg–Y–Zn alloys. J Mater Sci. 2010;45(9):2510–2517. doi: 10.1007/s10853-010-4223-z

22.

Itoi

, Inazawa

, Yamasaki

, Microstructure and mechanical properties of Mg-Zn-Y alloy sheet prepared by hot-rolling. Mater Sci Eng. 2013;560:216–223. doi: 10.1016/j.msea.2012.09.059

23.

Yamasaki

, Hashimoto

, Hagihara

, Effect of multimodal microstructure evolution on mechanical properties of Mg–Zn–Y extruded alloy. Acta Mater. 2011;59(9):3646–3658. doi: 10.1016/j.actamat.2011.02.038

24.

Wei

, Dunlop

, Westengen

The intergranular microstructure of cast Mg-Zn and Mg-Zn-rare earth alloys. Metall Mater Trans. 1995;26(8):1947–1955. doi: 10.1007/BF02670666

25.

, Wang

, Effect of Nd and Y addition on microstructure and mechanical properties of as-cast Mg–Zn–Zr alloy. J Alloy Compd. 2007;427(1):115–123. doi: 10.1016/j.jallcom.2006.02.054

26.

Liang

M-j

, Liao

H-h

, Ding

W-j

, Microstructure characterization on Mg-2Nd-4Zn-1Zr alloy during heat treatment. Trans Nonferr Metal Soc. 2012;22(10):2327–2333. doi: 10.1016/S1003-6326(11)61467-2

27.

Nie

J-F.

Precipitation and hardening in magnesium alloys. Metall Mater Trans. 2012;43(11):3891–3939. doi: 10.1007/s11661-012-1217-2

28.

Kim

J-K

, Ko

W-S

, Sandlöbes

, The role of metastable LPSO building block clusters in phase transformations of an Mg-Y-Zn alloy. Acta Mater. 2016;112:171–183. doi: 10.1016/j.actamat.2016.04.016

29.

Shao

, Yang

, Ma

XL.

Strengthening and toughening mechanisms in Mg–Zn–Y alloy with a long period stacking ordered structure. Acta Mater. 2010;58(14):4760–4771. doi: 10.1016/j.actamat.2010.05.012

30.

Chen

, Zhang

, Wang

, Effects of Zn content on microstructures and mechanical properties of Mg–Zn–RE–Sn–Zr–Ca alloys. Mater Sci Eng. 2014;607:17–27. doi: 10.1016/j.msea.2014.03.111

31.

Chen

, Wang

, Zhang

, Development of a new magnesium alloy ZW21. Mater Des. 2013;44:555–565. doi: 10.1016/j.matdes.2012.08.040

32.

Wang

, Zhang

, Cui

, Effect of Er and Nd addition on microstructure and mechanical properties of as-cast ZK60 alloy. J Chin Rare Earth Soc. 2006;24(6):710–715. (in Chinese).

33.

Zhang

, Zeng

, Liu

, Effects of yttrium on microstructure and mechanical properties of hot-extruded Mg–Zn–Y–Zr alloys. Mater Sci Eng. 2004;373(1):320–327. doi: 10.1016/j.msea.2004.02.007

34.

Zhang

, Yu

, Zhu

, Study on as-cast microstructures and solidification process of Mg–Zn–Y alloys. J Non Cryst Solids. 2008;354(14):1564–1568. doi: 10.1016/j.jnoncrysol.2007.08.049

35.

Tang

P-Y

, Tang

B-Y

, Peng

L-M

, Effect of Y and Zn substitution on elastic properties of 6H-type ABCBCB LPSO structure in Mg₉₇Zn₁Y₂ alloy. Mater Chem Phys. 2012;131(3):634–641. doi: 10.1016/j.matchemphys.2011.10.028

36.

Amiya

, Ohsuna

, Inoue

Long-period hexagonal structures in melt-spun Mg₉₇Ln₂Zn₁ (Ln=lanthanide metal) alloys. Mater Trans. 2003;44(10):2151–2156. doi: 10.2320/matertrans.44.2151

37.

HQ.

Principle of metal solidification. Beijing: China Machine Press; 2007. (in Chinese).

38.

Cordero

, Knight

, Schuh

CA.

Six decades of the Hall–Petch effect–a survey of grain-size strengthening studies on pure metals. Int Mater Rev. 2016;61(8):495–512. doi: 10.1080/09506608.2016.1191808

The microstructure and mechanical properties of as-cast Mg–4Y/Nd–2Zn alloys

Abstract

Keywords

Introduction

Experimental

Results and discussion

Microstructure

Mechanical properties

Conclusions

Footnotes

Disclosure statement

References