Precipitation Behavior and Strengthening Mechanism of Second Phases in AZ31-1.3Ca-1.0Sm-0.3La Alloy

Abstract:

A new type of AZ31-1.3Ca-1.0Sm-0.3La alloy was obtained in this study by adding Ca, Sm and La to AZ31 alloy. Detailed analysis results on second phases showed that Al₂Ca phases, Al₂Sm phases with two kinds of morphologies formed in as-cast AZ31-1.3Ca-1.0Sm-0.3La alloy besides Mg₁₇Al₁₂ phases, and La atoms mainly dissolved in Al₂Ca/Sm phases. The average grain size of as-cast AZ31-1.3Ca-1.0Sm-0.3La alloys was 212 μm and the grain sizes distributions were uniform. After the hot extrusion, the average grain size decreased to 5.4 μm and the grain sizes distributions were uneven. The base texture of as-extruded AZ31-1.3Ca-1.0Sm-0.3La alloy was strong, and the maximum density value was 3.25. The yield strength, ultimate tensile strength and elongation of as-extruded AZ31-1.3Ca-1.0Sm-0.3La alloy was 216 MPa, 280 MPa and 16% at RT, and 145 MPa, 188 MPa and 42% at 150°C, respectively, which are much higher than those of the common MB2 alloy both at the room temperature and 150 °C.

• Periodical: Materials Science Forum (Volume 993)
• Pages: 307-312
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.993.307
• Online since: May 2020
• Authors: Li Fu, Wen Xin Hu, Qi Chi Le*, Zheng Jia
• Keywords: AZ31 Alloy, Ca, La, Microstructure, Sm, Tensile Properties

References

[1] B. Smola,I.Stulı́ková,F. von Buch,et al. Structural Aspects of High Performance[J]. Mater. Sci. Eng. A,2002, 324: 113-117.

DOI: 10.1016/s0921-5093(01)01291-6

[2] A. Jain,O. Duygulu,D. W. Brown, et al. Grain Size Effects on the Tensile Properties and Deformation Mechanisms of a Magnesium Alloy, AZ31B, sheet[J]. Mater. Sci. Eng. A,2008, 486:545-555.

DOI: 10.1016/j.msea.2007.09.069

[3] F. K. Abu-Farha,M. R. Khraisheh. Mechanical Characteristics of Superplastic Deformation of AZ31 Magnesium Alloy[J].J. Mater. Eng. Perform, 2007, 16:192-199.

DOI: 10.1007/s11665-007-9031-5

[4] H. Zhang, W. Jin,J. F. Fan, et al. Grain Refining and Improving Mechanical Properties of a Warm Rolled AZ31 Alloy Plate[J].Mater. Lett., 2014, 135:31-34.

DOI: 10.1016/j.matlet.2014.07.130

[5] H. Zhang,Y. Liu,J. F. Fan, et al. Microstructure Evolution and Mechanical Properties of Twinned AZ31 Alloy Plates at Lower Elevated Temperature[J]. J. Alloys Compd., 2014, 615: 687-692.

DOI: 10.1016/j.jallcom.2014.07.045

[6] M. Z. Li,Y. Q. Wang,C. Li,et al. Effects of Neodymium Rich Rare Earth Elements on Microstructure and Mechanical Properties of as Cast AZ31 Magnesium Alloy[J].Mater. Sci. Tech., 2011,27:1138-1142.

DOI: 10.1179/026708310x12668415533883

[7] J. Zhang, M. Zhang, J. Meng, et al. Microstructures and Mechanical Properties of Heat-resistant High-pressure Die-Cast Mg-4Al-xLa-0.3Mn (x=1, 2, 4, 6) Alloys[J]. Mater. Sci. Eng. A., 2010, 527: 2527-2537.

DOI: 10.1016/j.msea.2009.12.048

[8] X. Y. Hu, P. H. Fu, D. StJohn, et al. On Grain Coarsening and Refining of the Mg-3Al alloy by Sm[J]. J. Alloys Compd., 2016, 663: 387-394.

DOI: 10.1016/j.jallcom.2015.11.193

[9] J. H. Jun, B. K. Park, J. M. Kim, et al. Effects of Ca Addition on Microstructure and Mechanical Properties of Mg-RE-Zn Casting Alloy[J]. Mater. Sci. Forum., 2005, 488-489: 107-110.

DOI: 10.4028/www.scientific.net/msf.488-489.107

[10] W. Q. Zhang, W. L. Xiao, F. Wang, et al. Development of Heat Resistant Mg-Zn-Al-based Magnesium Alloys by Addition of La and Ca: Microstructure and Tensile Properties[J]. J. Alloys Compd., 2016, 684: 8-14.

DOI: 10.1016/j.jallcom.2016.05.137

[11] Y. A. Chen, L. Jin, D. Fang, et al. Effects of Calcium, Samarium Addition on Microstructure and Mechanical Properties of AZ61 Magnesium Alloy[J]. J. Rare Earths., 2015, 33: 86-92.

DOI: 10.1016/s1002-0721(14)60387-2

[12] L. Fu, X. B. Wang, P. L. Gou, et al. Microstructures and Tensile Properties of AZ91 Magnesium Alloys with Ca, Sm, and La Elements Additions[J]. Adv. Eng. Mater., 2017, 19(12): 1700230.

DOI: 10.1002/adem.201700230

[13] L. Fu, Q. C. Le, P. L. Gou, et al. Effects of Ca and RE Additions on the Precipitation and Microstructure of as-Cast AZ91 Alloy[J]. Appl. Mech. Mater., 2017, 865: 30-35.

DOI: 10.4028/www.scientific.net/amm.865.30

[14] G. Cacciamani, R. Ferro. Thermodynamic Modeling of Some Aluminium-Rare Earth Binary Systems: Al-La, Al-Ce and Al-Nd[J]. Calphad., 2001, 25(4): 583-597.

DOI: 10.1016/s0364-5916(02)00009-3

[15] M. Aljarrah, M. Medraj, X. Wanga, et al. Experimental Investigation of the Mg-Al-Ca System[J]. J. Alloys Compd., 2007, 436: 131-141.

[16] B.S. Murty, S.A. Kori, M. Chakraborty. Grain Refinement of Aluminium and its Alloys by Heterogeneous Nucleation and Alloying[J]. Int. Mater. Rev., 2002, 47: 3-29.

DOI: 10.1179/095066001225001049