Microstructure and Mechanical Behavior of Squeeze Casting Mg-8Gd-2Y-0.4Zr Alloy

Abstract

Microstructure and mechanical behavior of the squeeze-casting and squeeze-casting plus T6 heat-treated Mg-8Gd-2Y-0.4Zr magnesium alloys at room and elevated temperatures were investigated. The experimental results showed that the T6 treated alloy aged at slightly high temperature exhibited good comprehensive strength and ductility. However, the strength of the tested alloys was not sensitive to the change of tensile temperature, i e, the yield strength and ultimate tensile strength did not decrease significantly with increasing tensile temperature, while the ductility increased greatly. In addition, the squeeze-casting alloy exhibited predominant intergranular fracture accompanied by minor transgranular rupture, and the tensile fracture mode for the T6 treated alloy had typical transgranular cleavage fracture.

Keywords

squeeze-casting / magnesium alloy / Mg-8Gd-2Y-0.4Zr / mechanical behavior

References

[1] Li JP, Yang Z, Liu T, et al. Microstructures of Extruded Mg-12Gd-1Zn-0.5Zr and Mg-12Gd-4Y-1Zn-0.5Zr Alloys[J]. Scripta Mater., 2007, 56: 137-140.

[2] Honma T, Ohkubo T, Kamado S, et al. Effect of Zn on Age-hardeningof Mg-2.0Gd-1.2Y-0.2 Zr Alloys[J]. Acta Mater., 2007, 55(12): 4 137-4 150.

[3] Mccool JI. Statistical Error in Crack Growth Parameters Deduced from Dynamic Fatigue Tests[J]. Int. J. Fatigue, 2004, 26(11): 1 207-1 215.

[4] Honma T, Ohkubo T, Hono K, et al. Chemistry of Nanoscale Precipitates in Mg-2.1Gd-0.6Y-0.2Zr (at%) Alloy Investigated by the Atom Probe Technique[J]. Mat. Sci. Eng. A, 2005, 395(1-2): 301-306.

[5] Ma SJ, Liu Y, Dong XH, et al. Microstructure and Flow Stress of Mg-12Gd-3Y-0.5Zr Magnesium Alloy[J]. J. Wuhan Univ. Technol., 2013, 28(1): 172-177.

[6] Yang Z, Li JP, Guo YC, et al. Precipitation Process and Effect on Mechanical Properties of Mg-9Gd-3Y-0.6Zn-0.5Zr Alloy[J]. Mat. Sci. Eng. A, 2007, 454-455(25): 274-280.

[7] Zhu R, Wu YJ, Liu JQ, et al. Microstructure and Properties of Mg-12Gd-3Y-0.5Zr Alloys Processed by ECAP and Extrusion[J]. J. Wuhan Univ. Technol., 2011, 26(6): 1 128-1 132.

[8] Du XH, Zhang EL. Microstructure and Mechanical Behavior of Semi-solid Die-casting AZ91D Magnesium Alloy[J]. Mater. Lett., 2007, 61(11-12): 2 333-2 337.

[9] Savas MA, Altintas S. Effects of Squeeze Casting on the Wide Freezing Range Binary Alloys[J]. Mat. Sci. Eng. A, 1993, 137(1-2): 227-231.

[10] Ghomashchi MR, Vikhrov A. Squeeze Casting: An Overview[J]. J. Mater. Process. Technol., 2000, 101(1-3): 1-9.

[11] Lin B, Zhang WW, Lou ZH, et al. Comparative Study on Microstructures and Mechanical Properties of the Heat-treated Al-5.0Cu-0.6MnxFe Alloys Prepared by Gravity Die-casting and Squeeze Casting[J]. Mater. Des., 2014, 59(20): 10-18.

[12] Zhai YB, Liu CM, Wang K. The Structural Evolutions of ZL109 Alloy and 7050 Alloy in the Semisolid Squeeze Casting Process[J]. J. Wuhan Univ. Technol., 2010, 25(1): 118-122.

[13] Xu H, Zhang X, Li HW, et al. Hot Deformation Behavior of Squeeze Casting SiC_p/2 A50 Matrix Composites[J]. J. Wuhan Univ. Technol., 2012, 27(3): 443-449.

[14] Sun ZZ, Hu H, Niu XP. Determination of Heat Transfer Coefficients by Extrapolation and Numerical Inverse Methods in Squeeze Casting of Magnesium Alloy AM60[J]. J. Mater. Process. Technol., 2011, 211(8): 1 432-1 440.

[15] Goh CS, Soh KS, Oon PH, et al. Effect of Squeeze Casting Parameters on the Mechanical Properties of AZ91-Ca Mg Alloys[J]. Mater. Des., 2010, 31: s50-s53.

[16] Horynová M, Zapletal J, Dolezˇal P, et al. Evaluation of Fatigue Life of AZ31 Magnesium Alloy Fabricated by Squeeze Casting[J]. Mater. Des., 2013, 45: 253-264.

[17] He SM. Study on the Microstructural Evolution, Properties and Fracture Behavior of Mg-Gd-Y-Zr(-Ca) Alloys[D]. Shanghai: Shanghai Jiao Tong University, 2007

[18] Wang QL. Study on the Microstructure and Mechanical Properties of Sand Mould Cast Mg-10Gd-3Y-Zr Alloy[D]. Shanghai: Shanghai Jiao Tong University, 2010

[19] Apps PJ, Karimzadeh H, King JF, et al. Precipitation Reactions in Magnesium-rare Earth Alloys Containing Yttrium, Gadolinium or Dysprosium[J]. Scripta Mater., 2003, 48(8): 1 023-1 028.

[20] Wan YC, Xiao HC, Jiang SN, et al. Microstructure and Mechanical Properties of Semi-continuous Cast Mg-Gd-Y-Zr Alloy[J]. Mat. Sci. Eng. A, 2014, 617: 243-248.

[21] Liang SQ, Guan DK, Chen L, et al. Precipitation and Its Effect on Age-hardening Behavior of As-cast Mg-Gd-Y Alloy[J]. Mater. Des., 2011, 32(1): 361-364.

[22] Tang LC, Liu CM, Chen ZY, et al. Microstructures and Tensile Properties of Mg-Gd-Y-Zr Alloy during Multidirectional Forging at 773K[J]. Mater. Des., 2013, 50: 587-596.