Comparative study on the microstructure and mechanical properties of Mg-Li-Al based alloys with yttrium and strontium addition

Abstract

The effects of yttrium and strontium on the microstructure and mechanical properties of Mg-11Li-3Al magnesium alloy (LA113) are compared and analyzed. Microstructures and phases of the alloys were studied with optical microscope (OM), scanning electron microscope (SEM), X-ray diffractometer (XRD) and energy dispersive spectrometer (EDS). Mechanical properties of alloys were measured with tensile tester. The results show that yttrium and/or strontium additions produce a strong grain refining effect in LA113 alloy. Al₂Y and Al₄Sr, etc. phases with different morphologies are verified and exist inside the grain or at the grain boundaries, which directly impact on the mechanical properties of LA113 alloy. The results of tensile tests show that, the as-extruded LA113-1Y-1Sr alloy obtains the optimal tensile property of which the tensile strength and elongation are 253.56 MPa and 18.12%, the tensile strength is increased by almost 25% compared with the asextruded LA113 alloy.

Keywords

Mg-Li-Al alloy / yttrium / strontium / microstructure / mechanical properties

References

[1] Wu L B, Cui C L, Wu R Z. Effects of Ce-rich RE Additions and Heat Treatment on the Microstructure and Tensile Properties of Mg-Li-Al-Zn-based Alloy[J]. Materials Science and Engineering A, 2011, 528: 2 174-2 179.

[2] Li M, Hao H, Zhang A M, et al. Effects of Nd on Microstructure and Mechanical Properties of As-cast Mg-8Li-3Al Alloy[J]. Journal of Rare Earths, 2012, 30(5): 492-496.

[3] LEI B, LE Q C, ZHANG Z Q, et al. Effect of Homogenization Treatment on Microstructure Evolution and the Distributions of RE and Zr Elements in Various Mg-Li-RE-Zr Alloys [J]. Journal of Magnesium and Alloys, 2013, 1(2): 139-144.

[4] Liu B, Zhang M L, Wu R Z. Effects of Nd on Microstructure and Mechanical Properties of As-cast LA141 alloys [J]. Materials Science and Engineering A, 2008, 487: 347-351.

[5] Zeng Y, Jiang B, Huang D H, et al. Effect of Ca addition on Grain Refinement of Mg-9Li-1Al Alloy[J]. Journal of Magnesium and Alloys, 2013, 1(4): 297-302.

[6] Mataumoto H, Watanabe S, Hanada S. Fabrication of Pure Al/Mg-Li Alloy Clad Plate and Its Mechanical Properties [J]. J. Mater. Process. Technol., 2005, 169: 9-15.

[7] Wang S R, Guo P Q, Yang L Y, et al. Microstructure and Mechanical Properties of AZ91 Alloys by Addition of Yttrium[J]. Journal of Materials Engineering and Performance, 2009, 18(2): 137-144.

[8] Wang T, Zhang M L, Niu Z Y, et al. Influence of Rare Earth Elements on Microstructure and Mechanical Properties of Mg-Li Alloys[J]. Journal of Rare Earths, 2006, 24: 797-800.

[9] Wu A R, Xia C Q. Study of the Microstructure and Mechanical Properties of Mg-rare Earth alloys[J]. Materials and Design, 2007, 28: 1 963-1 967.

[10] Chang H W, Qiu D, Taylor J A, et al. The Role of Al2Y in Grain Refinement in Mg-Al-Y Alloy System[J]. Journal of Magnesium and Alloys, 2013, 1(2): 115-121.

[11] Yang M B, Pan F S, Cheng R J, et al. Comparation about Efficiency of Al-10Sr and Mg-10Sr Master Alloys to Grain Efinement of AZ31 Magnesium alloy[J]. J. Mater. Sci., 2007, 42: 10 074-10 079.

[12] Liu T, Wu S D, Li S X, et al. Microstructure Evolution of Mg-14% Li-1% Al Alloy During the Process of Equal Channel Angular Pressing [J]. Materials Science and Engineering A, 2007, 460–461: 499-503.

[13] Zhang M X, Kelly P M, Easton M A, et al. Crystallographic Study of Grain Refinement in Aluminum Alloys Using the Edge-toedge Matching Model [J]. Acta Materialia, 2005, 53: 1 427-1 438.

[14] Zhang M X, Kelly P M, Qian M, et al. Crystallography of Grain Refinement in Mg-Al Based Alloys [J]. Acta Materialia, 2005, 53: 3 261-3 271.

[15] Li R H, Pan F S, Jiang B, et al. Effects of Yttrium and Strontium Additions on As-cast Microstructure of Mg-14Li-1Al Alloys[J]. Transactions of Nonferrous Metals Society of China, 2011, 21: 778-783.

[16] Jiang B, Qiu D, Zhang M X, et al. A New Approach to Grain Refinement of an Mg-Li-Al Cast Alloy [J]. Journal of Alloys and Compounds, 2010, 492: 95-98.

[17] Wang T, Wu R Z, Zhang M L, et al. Effects of Calcium on the Microstructures and Tensile Properties of Mg-5Li-3Al Alloys [J]. Materials Science and Engineering A, 2011, 528: 5 678-5 684.

[18] Meng X R, Wu R Z, Zhang M L, et al. Microstructures and Properties of Superlight Mg-Li-Al-Zn Wrought Alloys[J]. Journal of Alloys and Compounds, 2009, 486: 722-725.

[19] Yang Y, Peng X D, Wen H M, et al. Influence of Extrusion on the Microstructure and Mechanical Behavior of Mg-9Li-3Al-xSr Alloys[J]. Metallurgical and Materials Transactions A, 2013, 44A: 1 101-1 113.