Effect of HFC-134a Concentration on High-temperature Oxidation Behaviour of Mg-8Gd-4Y Alloy

ZHAO Xinyi; XIAO Yao; QIN Hong; SUN Yang; LI Tianqing

doi:10.3969/j.issn.1674-6457.2026.04.005

PDF(18083 KB)

Journal of Netshape Forming Engineering ›› 2026, Vol. 18 ›› Issue (4) : 45-55. DOI: 10.3969/j.issn.1674-6457.2026.04.005

Light Alloy Forming

Effect of HFC-134a Concentration on High-temperature Oxidation Behaviour of Mg-8Gd-4Y Alloy

ZHAO Xinyi^*, XIAO Yao, QIN Hong, SUN Yang, LI Tianqing

Author information +

History +

Abstract

The work aims to systematically investigate the effect of HFC-134a concentration on the high-temperature oxidation behavior of magnesium alloys to elucidate the flame-retardant mechanism of HFC-134a/CO₂ mixed gases, determine the optimal concentration range of HFC-134a for developing effective protective atmospheres for magnesium alloys. The Mg-8Gd-4Y alloy was selected as the experimental material. Isothermal oxidation experiments were conducted under varying temperature and HFC-134a concentrations. The composition and microstructure of the resulting oxide layers were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Thermodynamic calculations were performed to analyze the formation mechanism of protective oxide layers. Results demonstrated that increasing HFC-134a concentration promoted the transformation of oxide layers from MgO to a composite structure containing MgF₂ and rare-earth oxides. At 600 ℃ (solid-state oxidation), discontinuous rare-earth oxide layers dominated by Y₂O₃ were observed. In contrast, at 700 ℃ (liquid-state oxidation), continuous rare-earth oxide layers with increased Gd₂O₃content were formed. The findings indicate that while higher HFC-134a concentrations enhance the protective properties of oxide layers, concentrations exceeding 10% lead to deteriorated surface quality of castings. Therefore, a 10% HFC-134a/CO₂ mixed gas is recommended as the optimal protective atmosphere for magnesium alloy processing.

Key words

magnesium alloy / high-temperature oxidation / HFC-134a concentration / oxide layer structure / thermodynamics

Cite this article

EndNote

Ris (Procite)

Bibtex

Download Citations

ZHAO Xinyi, XIAO Yao, QIN Hong, SUN Yang, LI Tianqing. Effect of HFC-134a Concentration on High-temperature Oxidation Behaviour of Mg-8Gd-4Y Alloy[J]. Journal of Netshape Forming Engineering. 2026, 18(4): 45-55 https://doi.org/10.3969/j.issn.1674-6457.2026.04.005

References

[1] ALIZADEH R, MAHMUDI R, NGAN A H W, et al. Microstructural Stability and Grain Growth Kinetics in an Extruded Fine-Grained Mg-Gd-Y-Zr Alloy[J]. Journal of Materials Science, 2015, 50(14): 4940-4951.
[2] SUN W H, SHI X Y, CINKILIC E, et al.Investigation of the Non-Equilibrium Solidification Microstructure of a Mg-4Al-2RE (AE42) Alloy[J]. Journal of Materials Science, 2016, 51(13): 6287-6294.
[3] SONG J F, SHE J, CHEN D L, et al.Latest Research Advances on Magnesium and Magnesium Alloys Worldwide[J]. Journal of Magnesium and Alloys, 2020, 8(1): 1-41.
[4] XU T C, YANG Y, PENG X D, et al.Overview of Advancement and Development Trend on Magnesium Alloy[J]. Journal of Magnesium and Alloys, 2019, 7(3): 536-544.
[5] 陈先华. 先进镁合金材料专题序言[J]. 精密成形工程, 2024, 16(11): 3.
CHEN X H.Preface to Advanced Magnesium Alloy Materials[J]. Journal of Netshape Forming Engineering, 2024, 16(11): 3.
[6] TAN Q Y, MO N, LIN C L, et al.Improved Oxidation Resistance of Mg-9Al-1Zn Alloy Microalloyed with 60 wt ppm Be Attributed to the Formation of a More Protective (Mg, Be)O Surface Oxide[J]. Corrosion Science, 2018, 132: 272-283.
[7] 王严, 谢吉林, 陈玉华, 等. 镁基复合材料制备技术研究现状[J]. 精密成形工程, 2022, 14(12): 119-127.
WANG Y, XIE J L, CHEN Y H, et al.Research Progress in Preparing Technology of Magnesium Matrix Composites[J]. Journal of Netshape Forming Engineering, 2022, 14(12): 119-127.
[8] TAN Q Y, ATRENS A, MO N, et al.Oxidation of Magnesium Alloys at Elevated Temperatures in Air: A Review[J]. Corrosion Science, 2016, 112: 734-759.
[9] 杨鸿智, 尹小文, 苏彦芳, 等. 镁合金零部件在汽车中的应用研究[J]. 汽车工艺师, 2023(10): 56-59.
YANG H Z, YIN X W, SU Y F, et al.Research on the Application of Magnesium Alloy Parts in Automobiles[J]. Auto Manufacturing Engineer, 2023(10): 56-59.
[10] 郭政佑, 贾昊阳, 王佳豪, 等. 镁合金及其复合材料电磁屏蔽性能研究进展[J]. 精密成形工程, 2023, 15(4): 9-24.
GUO Z Y, JIA H Y, WANG J H, et al.Research Progress on Electromagnetic Shielding Performance of Magnesium Alloy and Its Composites[J]. Journal of Netshape Forming Engineering, 2023, 15(4): 9-24.
[11] HAN D, ZHANG J, HUANG J F, et al.A Review on Ignition Mechanisms and Characteristics of Magnesium Alloys[J]. Journal of Magnesium and Alloys, 2020, 8(2): 329-344.
[12] XU W Q, BIRBILIS N, SHA G, et al.A High-Specific-Strength and Corrosion-Resistant Magnesium Alloy[J]. Nature Materials, 2015, 14(12): 1229-1235.
[13] CZERWINSKI F.The Oxidation Behaviour of an AZ91D Magnesium Alloy at High Temperatures[J]. Acta Materialia, 2002, 50(10): 2639-2654.
[14] TEKUMALLA S, GUPTA M.An Insight into Ignition Factors and Mechanisms of Magnesium Based Materials: A Review[J]. Materials & Design, 2017, 113: 84-98.
[15] TAN Q Y, YIN Y, MO N, et al.Recent Understanding of the Oxidation and Burning of Magnesium Alloys[J]. Surface Innovations, 2019, 7(2): 71-92.
[16] SCHLÜTER K, SHI Z M, ZAMPONI C, et al. Corrosion Performance and Mechanical Properties of Sputter-Deposited MgY and MGGD Alloys[J]. Corrosion Science, 2014, 78: 43-54.
[17] CAO F Y, SHI Z M, SONG G L, et al.Corrosion Behaviour in Salt Spray and in 3.5% NaCl Solution Saturated with Mg(OH)₂ of As-Cast and Solution Heat-Treated Binary Mg-X Alloys: X=Mn, Sn, Ca, Zn, Al, Zr, Si, Sr[J]. Corrosion Science, 2013, 76: 60-97.
[18] CAO F Y, SHI Z M, SONG G L, et al.Influence of Hot Rolling on the Corrosion Behavior of Several Mg-X Alloys[J]. Corrosion, 2015, 90: 176-191.
[19] ABASPOUR S, CÁCERES C H. Thermodynamics-Based Selection and Design of Creep-Resistant Cast Mg Alloys[J]. Metallurgical and Materials Transactions A, 2015, 46(12): 5972-5988.
[20] JOHNSTON S, SHI Z M, ATRENS A.The Influence of pH on the Corrosion Rate of High-Purity Mg, AZ91 and ZE41 in Bicarbonate Buffered Hanks' Solution[J]. Corrosion Science, 2015, 101: 182-192.
[21] ATRENS A, SONG G L, LIU M, et al.Review of Recent Developments in the Field of Magnesium Corrosion[J]. Advanced Engineering Materials, 2015, 17(4): 400-453.
[22] 沈朝, 王志鹏, 胡波, 等. 镁合金抗高温氧化机理研究进展[J]. 金属学报, 2023, 59(3): 371-386.
SHEN Z, WANG Z P, HU B, et al.Research Progress on the Mechanisms Controlling High-Temperature Oxidation Resistance of Mg Alloys[J]. Acta Metallurgica Sinica, 2023, 59(3): 371-386.
[23] 李多娇, 程春龙, 乐启炽, 等. 镁合金氧化机理研究进展[J]. 材料导报, 2023, 37(1): 167-175.
LI D J, CHENG C L, LE Q C, et al.Research Progress on Oxidation Mechanism of Magnesium Alloys[J]. Materials Reports, 2023, 37(1): 167-175.
[24] 李景仁, 谢东升, 张栋栋, 等. Ce添加对Mg-Ca挤压合金力学性能与热稳定性影响研究[J]. 精密成形工程, 2023, 15(2): 1-10.
LI J R, XIE D S, ZHANG D D, et al.Effect of Ce on Mechanical Property and Thermal Stability of Extruded Mg-Ca Alloy[J]. Journal of Netshape Forming Engineering, 2023, 15(2): 1-10.
[25] 尹雪雁, 于建民, 张治民. Mg-13Gd-4Y-0.5Zr镁合金多向锻造组织和性能研究[J]. 精密成形工程, 2014, 6(6): 68-71.
YIN X Y, YU J M, ZHANG Z M.Microstructure and Performance of Mg-13Gd-4Y-0.5Zr Magnesium Alloy under Multidirectional Forging[J]. Journal of Netshape Forming Engineering, 2014, 6(6): 68-71.
[26] 范才河, 陈刚, 严红革, 等. 稀土在镁及镁合金中的作用[J]. 材料导报, 2005, 19(7): 61-63.
FAN C H, CHEN G, YAN H G, et al.Effect of Rare Earth in Magnesium and Magnesium Alloys[J]. Materials Review, 2005, 19(7): 61-63.
[27] SIN S L, ELSAYED A, RAVINDRAN C.Inclusions in Magnesium and Its Alloys: A Review[J]. International Materials Reviews, 2013, 58(7): 419-436.
[28] STALNICHENKO O, LYSENKO T, SHAMOV O, et al.Features of Magnesium Alloy Protection Technologies in Die Casting[C]//Advanced Manufacturing Processes V. Cham: Springer, 2024: 326-334.
[29] YUAN C M, YU L F, LI C, et al.Thermal Analysis of Magnesium Reactions with Nitrogen/Oxygen Gas Mixtures[J]. Journal of Hazardous Materials, 2013, 260: 707-714.
[30] NIE H Q, SCHOENITZ M, DREIZIN E L.Oxidation of Magnesium: Implication for Aging and Ignition[J]. The Journal of Physical Chemistry C, 2016, 120(2): 974-983.
[31] DVORSKY D, KUBASEK J, VOJTECH D, et al.The Effect of Y, Gd and Ca on the Ignition Temperature of Extruded Magnesium Alloys[J]. Materiali in Tehnologije, 2020, 54(5): 669-675.
[32] ZHANG L P, LIN H L, YANG H Z, et al.Effect of F Content on the Protection of Melted Magnesium Alloy[J]. Revista de Chimie, 2020, 71(3): 588-594.
[33] HOLTZER M, BOBROWSKI A.Magnesium Melt Protection by Covering Gas[J]. Archives of Foundry Engineering, 2008, 8: 131-136.
[34] GUO Y C, LI J P, LI J S, et al.Mg-Gd-Y System Phase Diagram Calculation and Experimental Clarification[J]. Journal of Alloys and Compounds, 2008, 450(1/2): 446-451.
[35] ZHAO H D, QIN G W, REN Y P, et al.The Maximum Solubility of Y in α-Mg and Composition Ranges of Mg₂₄Y_5-_x and Mg₂Y_1-_x Intermetallic Phases in Mg-Y Binary System[J]. Journal of Alloys and Compounds, 2011, 509(3): 627-631.
[36] WANG X Z, ZHANG P, JIANG X M, et al.Influence of Solid-Solution Processes on the Microstructure and Dynamic Impact Behavior of Cast Mg-Gd-Y-Based Alloys[J]. Vacuum, 2025, 238: 114280.
[37] TROWBRIDGE L D.Potential Hazards Relating to Pyrolysis of c-C₄F₈O, n-C₄F₁₀, and c-C₄F₈ in Selected Gaseous Diffusion Plant Operations[R]. Oak Ridge National Lab.(ORNL), Oak Ridge, TN(United States), 2000.
[38] 陈虎魁. 镁熔体与保护性含氟气体反应过程的热力学分析[J]. 热加工工艺, 2013, 42(19): 63-66.
CHEN H K.Thermo-Dynamic Analysis on Reaction of Magnesium Melt with Fluorine-Containing Cover Gase[J]. Hot Working Technology, 2013, 42(19): 63-66.
[39] 曾一文, 吴国华. 镁熔体在HFC-32/CO₂气氛中的高温氧化行为[J]. 中国有色金属学报, 2013, 23(4): 1145-1151.
ZENG Y W, WU G H.Oxidation Behavior of Molten Magnesium in Atmospheres of HFC-32/CO₂ at High Temperature[J]. The Chinese Journal of Nonferrous Metals, 2013, 23(4): 1145-1151.