本研究使用 Mg-5Y (wt%) 合金作為基材以 325 ℃、350 ℃為處理溫度以120°及路徑 Bc 之等徑轉角擠製加工（Equal Channel Angular Pressing, ECAP）進行擠製2與4道次(pass)，以將富Y之顆粒細化及均勻化後再進行熱氫製程，處理溫度以350 ℃、時間為36小時，且於 0.34 MPa 氫氣壓力下進行內部氫化後再真空下放氫1小時，並分析試片之成分、微觀結構及機械性質以探討晶粒細化是否對於內部氫化作用之機械性質有影響。
在經過熱氫製程後，以ECAP 350 ℃ 擠製4道次的試片有最高之硬度及強度，其原因在於試片在ECAP後有最小的晶粒尺寸。研究結果顯示ECAP會降低鎂晶粒尺寸、富Y顆粒尺寸以及內部氫化處理後產生之氫化物YH2之粒徑尺寸。在同樣的熱氫製程參數下，鎂晶粒尺寸下降會使YH2的生成量變多及YH2粒徑尺寸下降，提升散佈強化效果；然而，因為退火作用及鎂基底中釔濃度大幅減少，造成固溶強化效果降低，導致試片在經過熱氫處理後機械性質降低。

In this study, Mg-5Y (wt%) alloy was used as the base material, 325 ℃, 350 ℃ as the processing temperature, 120° and path Bc Equal Channel Angular Pressing (ECAP) for extrusion 2 and 4 Pass (pass), to refine and homogenize the Y-rich particles before the hot hydrogen process, the treatment temperature is 350 ℃, the time is 36 hours, and the internal hydrogenation is carried out under the hydrogen pressure of 0.34 MPa, and then the hydrogen is released under vacuum 1 hour, and analyze the composition, microstructure and mechanical properties of the test piece to explore whether the grain refinement has an impact on the mechanical properties of the internal hydrogenation.
After the hot hydrogen process, the test piece extruded with ECAP 350 ℃ for 4 passes has the highest hardness and strength. The reason is that the test piece has the smallest grain size after ECAP. The research results show that ECAP can reduce the size of Mg grains, Y-rich grains and the grain size of hydride YH2 produced after internal hydrogenation treatment. Under the same hot hydrogen process parameters, the reduction of magnesium grain size will increase the amount of YH2 produced and the particle size of YH2 will decrease, which will improve the effect of dispersion strengthening; The strengthening effect is reduced, resulting in a decrease in the mechanical properties of the test pieces after hot hydrogen treatment.

[1] J. W. Kong, Q. N. Shi, J. H. Wang, J. H. Yi, H. C. Xie, L. W. Chen, “Microstructure and properties of Ag-1.33%Mg-0.54%Ni alloy after severe plastic deformation and internal oxidation”, Rare metal materials and engineering 42, 2013, pp. 32-36.
[2] S. Morozumi, H. Saikawa, T. Minegishi, M. Matsuyama, K. Watanabe, M. Iijima, M. Ohtsuki, “Structure and mechanical properties of internally hydrided Mg-Ⅲa transition metal alloys”, Journal of materials science 31, 1996, pp. 4647-4654.
[3] X. Shi, J. Zou, C. Liu, L. Cheng, D. Li, X. Zeng, W. Ding, “Study on hydrogenation behaviors of a Mg-13Y alloy”, Internal journal of hydrogen energy 39, 2014, pp. 8303-8310.
[4] L. Gao, R.S. Chen, E.H. Han, “Solid solution strengthening behaviors in binary Mg-Y single phase alloys”, Journal of alloys and compounds 472, 2009, pp. 234-240.
[5] I. Polmear, D. StJohn, J. F. Nie, M. Qian, “6-Magnesium alloys”, Light alloys (fifth edition) metallurgy of the light metals, 2017, pp. 287-367.
[6] 張文政、劉正、毛萍莉，「鎂金屬提煉和精煉工藝的研究進展」， 機械傳動雜誌 11 期，民國 103 年。
[7] I. Polmear, D. StJohn, J. F. Nie, M. Qian, “3-Casting of light alloys”, Light alloys (fifth edition) metallurgy of the light metals, 2017, pp. 109-156.
[8] M. K. Kulekci, “Magnesium and its alloys applications in automotive industry”, The international journal of advanced manufacturing technology volume 39, 2008, pp. 861-865.
[9] H. Watarai, “Trend of research and development for magnesium alloys”, Quarterly review 18, 2006, pp. 84-97.
[10] I. Polmear, D. StJohn, J. F. Nie, M. Qian, “1-The light metals”, Light alloys (fifth edition) metallurgy of the light metals, 2017, pp. 1-29.
[11] C. Moosbrugger, “Chapter 1 introduction to magnesium alloys”, Engineering properties of magnesium alloys, 2017, pp. 1-10.
[12] S. Zhang, X. Zhang, C. Zhao, J. Li, Y. Song, C. Xie, H. Tao, Y. Zhang, Y. He, Y. Jiang, Y. Bian, “Research on an Mg-Zn alloy as a degradable biomaterial”, Acta biomaterialia 6, 2010, pp. 626-640.
[13] B. L. Mordike, T. Ebert, “Magnesium properties-applicationspotential”, Materials science and engineering A 302, 2001, pp. 37-45.
[14] A. A. Luo, “Recent magnesium alloy development for elevated temperature applications”, International materials reviews 49, 2004, pp. 13-30.
[15] A. Kielbus, T. Rzychon, “Mechanical and creep properties of Mg-4Y3RE and Mg-3Nd-1Gd magnesium alloy”, Procedia engineering 10, 2011, pp. 1835-1840.
[16] K. Luo, L. Zhang, G. Wu, W. Liu, W. Ding, “Effect of Y and Gd content on the microstructure and mechanical properties of Mg-Y-RE alloys”, Journal of magnesium and alloys 7, 2019, pp. 345-354
[17] L. Gao, R. S. Chen, E. H. Han, “Solid solution strengthening behaviors in binary Mg-Y single phase alloys”, Journal of alloys and compounds 472, 2009, pp. 234-240.
[18] C. H. Caceres, D. M. Rovera, “Solid solution strengthening in concentrated Mg-Al alloys”, Journal of light metals 1, 2001, pp. 151- 156.
[19] C. H. Caceres, A. Blake, “The strength of concentrated Mg-Zn solid solutions”, Physica status solidi 194, 2002, pp. 147-158.
[20] R. Lapovok, E. Zolotoyabko, A. Berner, V. Skripnyuk, E. Lakin, N. Larianovskyb, C. Xuc, E. Rabkinb, “Hydrogenation effect on microstructure and mechanical properties of Mg-Gd-Y-Zn-Zr alloys”, Materials science and engineering A 719, 2018, pp. 171-177.
[21] H. Okamoto, “Mg-Y (Magnesium-Yttrium)”, Journal of phase equilibria and diffusion 31, 2010, pp. 199.
[22] B. L. Wu, Y. H. Zhao, X. H. Du, Y. D. Zhang, F. Wagner, C. Esling, “Ductility enhancement of extruded magnesium via yttrium addition”, Materials science and engineering A 527, 2010, pp.4334-4340.
[23] L. Gao, R. S. Chen, E. H. Han, “Effects of rare-earth elements Gd and Y on the solid solution strengthening of Mg alloys”, Journal of alloys and compounds 481, 2009, pp. 379-384.
[24] J. Tan, Y. H. Sun, H. B. Xie, B. Z. Sun, Y. Qi, “Atomic-resolution investigation of Y-rich solid solution with an invariable orientation in Mg-Y binary alloy”, Journal of alloys and compounds 766, 2018, pp. 716-720.
[25] C. C. Kammerer, N. S. Kulkarni, R. J. Warmack, Y. H. Sohn, “Interdiffusion and impurity diffusion in polycrystalline Mg solid solution with Al or Zn”, Journal of alloys and compounds 617, 2014, pp. 968-974.
[26] D. Nagarajan, X. Ren, C. H. Cáceres, “Anelastic behavior of Mg-Al and Mg-Zn solid solutions”, Materials science and engineering: A 696, 2017, pp. 387-392.
[27] R. Abbaschian, L. Abbaschian, R. E. Reed-Hill, Physical metallurgy principles 4th edition, 2008
[28] A. Styczynski, C. Hartig, J. Bohlen, D. Letzig, “Cold rolling textures in AZ31 wrought magnesium alloy”, Scripta materialia 50, 2004, pp. 943-947.
[29] H. Meckings, U. F. Kocks, “Kinetics of flow and strain-hardening”, Acta metallurgica 29, 1981, pp. 1865-1875.
[30] M. X. Guo, M. P. Wang, L. F. Cao, R. S. Lei, “Work softening characterization of alumina dispersion strengthened copper alloys”, Materials characterization 58, 2007, pp. 928-935.
[31] Y. C. Zhao, M. C. Zhao, R. Xu, L. Liu, J. X. Tao, C. Gao, C. Shuai, A. Atrens, “Formation and characteristic corrosion behavior of alternately lamellar arranged α and β in as-cast AZ91 Mg alloy”, Journal of alloys and compounds 770, 2019, pp. 549-558.
[32] L. B. Ren, G. F. Quan, M. Y. Zhou, Y. Y. Guo, Z. Z. Jiang, Q. Tang, “Effect of Y addition on the aging hardening behavior and precipitation evolution of extruded Mg-Al-Zn alloys”, Materials science and engineering: A 690, 2017, pp. 195-207.
[33] J. Miao, W. Sun, A. D. Klarner, A. A. Luo, “Interphase boundary segregation of silver and enhanced precipitation of Mg17Al12 phase in a Mg-Al-Sn-Ag alloy”, Scripta materialia 154, 2018, pp. 192-196.
[34] B. Q. Shi, Y. Q. Cheng, H. Yan, R. S. Chen, W. Ke, “Hall-Petch relationship, twinning responses and their dependences on grain size in the rolled Mg-Zn and Mg-Y alloys”, Materials science and engineering A 743, 2019, pp. 558-566.
[35] T. Sadhasivama, H. T. Kimb, S. Jungc, S. H. Rohd, J. H. Parka, H. Y. Junga, “Dimensional effects of nanostructured Mg/MgH2 for hydrogen storage applications: A review”, Renewable and sustainable energy reviews 72, 2017, pp. 523-534.
[36] M. Szymanski, B. Michalski, M. Leonowicz, Z. Miazga, “Application of the HDDR method for recycling of Nd-Fe-B magnets”, IEEE international magnetics conference, 2015.
[37] Y. Zhang, J. Han, S. Liu, F. Wan, H. Tian, X. Zhang, C. Wang, J. Yang, Y. Yang, “Coercivity enhancement by grain refinement for anisotropic Nd2Fe14B-type magnetic powders”, Scripta materialia 110, 2016, pp. 57-60.
[38] M. Szymański, B. Michalski, M. Leonowicz, Z. Miazga, “Structure and properties of Nd-Fe-B alloy subjected to HDDR process”, Archives of metallurgy and materials 61, 2016, pp. 217-220.
[39] L. Hu, Y. Wu, Y. Yuan, H. Wang, “Microstructure nanocrystallization of a Mg-3 wt.% Al-1 wt.% Zn alloy by mechanically assisted hydriding-dehydriding”, Materials letters 62, 2008, pp. 2984-2987.
[40] Z. Z. Xie, J. F. Fan, H. B. Dong, F. Zhou, B. S. Xu, “Microstructure evolution and nano-crystalline production of Mg-9Al-Zn alloy during HDDR processing”, Journal of alloys and compounds 699, 2017, pp. 841-848.
[41] H. Takamura, T. Miyashita, A. Kamegawa, M. Okada, “Grain size refinement in Mg-Al-based alloy by hydrogen treatment”, Journal of alloys and compounds 356-357, 2003, pp. 804-808.
[42] A. Kamegawa, T. Funayama, J. Takahashi, H. Takamura, M. Okada, “Grain refinements of Al-Mg alloy by hydrogen heat-treatments”, Materials transactions 46, 2005, pp. 2449-2453.
[43] T. Miyazawa, Y. Kobayashi, A. Kamegawa, H. Takamura, M. Okada, “Grain size refinements of Mg Alloy (AZ61, AZ91, ZK60) by HDDR treatments”, Materials transactions 45, 2004, pp. 384-387.
[44] O. N. Senkov, F. H. Froes, “Thermohydrogen processing of titanium alloys”, International journal of hydrogen energy 24, 1999, pp. 565- 576.
[45] Z. Sun, W. Zhou, H. Hou, “Strengthening of Ti-6Al-4V alloys by thermohydrogen processing”, International journal of hydrogen energy 34, 2009, pp. 1971-1976.
[46] Y. Zhang, S. Q. Zhang, “Hydrogenation characteristics of TI-6AL-4V cast alloy and its microstructural modification by hydrogen treatment”, International journal of hydrogen energy 22, 1997, pp. 161-168.
[47] J. Nakahigashi, H. Yoshimura, “Ultra-fine grain refinement and tensile properties of titanium alloys obtained through protium treatment”, Journal of alloys and compounds 330-332, 2002, pp. 384-388.
[48] H. Liu, J. Cao, P. He, J. C. Feng, “Effect of hydrogen on diffusion bonding of commercially pure titanium and hydrogenated Ti6Al4V alloys”, International journal of hydrogen energy 34, 2009, pp. 1108- 1113.
[49] X. Li, X. Chen, B. Li, N. Chen, J. Chen, “Grain refinement mechanism of Ti-55 titanium alloy by hydrogenation and dehydrogenation treatment”, Materials characterization 157, 2019.
[50] H. Yoshimura, “Mezzoscopic grain refinement and improved mechanical properties of titanium materials by hydrogen treatments”, International journal of hydrogen energy 22, 1997, pp. 145-150.
[51] H. Yoshimura, J. Nakahigashi, “Ultrafine grain refinement and superplasticity of titanium alloys obtained through protium treatment”, International journal of hydrogen energy 27, 2002, pp. 769-774.
[52] X. W. Liu, Y. Q. Su, L. S. Luo, K. Li, F. Y. Dong, J .J. Guo, H. Z. Fu, “Effect of hydrogen treatment on solidification structures and mechanical properties of Ti-Al alloys”, International journal of hydrogen energy 36, 2011, pp. 3260-3267.
[53] X. Li, G. Jia, F. Qu, H. Wu, J. Chen, “Ultrafine grain refinement and superplasticity of Ti-55 alloy obtained by hydrogen absorption and desorption”, Journal of materials engineering and performance 27, 2018, pp. 3472-3477.
[54] B. Lagowski, “Metallography of hydrided ZE63 magnesium casting alloy”, A F S trans 84, 1976, pp. 151.
[55] Z. Y. Zhao, “High performance ZM8 casting magnesium alloy processed by hydrogenation heat treatment (in Chinese)”, Aeronaut mater 1, 2011, pp. 1-7.
[56] A. Züttel, “Materials for hydrogen storage”, Material today 6, 2003, pp. 24-33.
[57] D. Chandra, J. J. Reilly, R. Chellappa, “Metal hydrides for vehicular applications: The state of the art”, JOM, 2006, pp. 26-32.
[58] K. Fu, X. Jiang, Y. Guo, S. Li, J. Zheng, W. Tian, X. Li, “Experimental investigation and thermodynamic assessment of the yttrium hydrogen binary system”, Progress in natural science: Materials international 28, 2018, pp. 332-336.
[59] K. Goc, W. Prendota, J. Przewo_znik, Ł. Gondek, C. Kapusta, A. Radziszewska, K. Mineo, A. Takasaki, “Magnetron sputtering as a method for introducing catalytic elements to magnesium hydride”, International journal of hydrogen energy 43, 2018, pp. 20836-20842.
[60] “ASTM E8E8M-09 standard test methods for tension testing of metallic materials”, ASTM international, 2011.
[61] Y. Yang, L. Peng, P. Fu, B. Hu, W. Ding, “Identification of NdH2 particles in solution-treated Mg-2.5%Nd (wt.%) alloy”, Journal of alloys and compounds 485, 2009, pp. 245-248.
[62] 莊東漢，「材料破損分析」，五南出版社，民國 96 年。
[63] A. Matin, F. F. Saniee, H. R. Abedi, “Microstructure and mechanical properties of Mg/SiC and AZ80/SiC nano-composites fabricated through stir casting method”, Materials science and engineering A 625, 2015, pp. 81-88.
[64] M. H. Korayem, R. Mahmudi, W. J. Poole, “Enhanced properties of Mg-based nano-composites reinforced with Al2O3 nano-particles”, Materials science and engineering A 519, 2009, pp. 198-203.
[65] S. F. Hassan, M. Gupta, “Development of high performance magnesium nano-composites using nano-Al2O3 as reinforcement”, Materials science and engineering A 392, 2005, pp. 163-168.
[66] S. S. Zhou, K. K. Deng, J. C. Li, S. J. Shang, W. Liang, J. F. Fan, “Effects of volume ratio on the microstructure and mechanical properties of particle reinforced magnesium matrix composite”, Materials and design 63, 2014, pp. 672-677.
[67] D. Setoyama, M. Ito, J. Matsunaga, H. Muta, M. Uno, S. Yamanaka, “Mechanical properties of yttrium hydride”, Journal of alloys and compounds 394, 2005, pp. 207-210.
[68] 李智堯 (2018)，不同轉角及道次之等徑轉角擠製對 AZ31/WS2INT鎂基複合材料微觀結構及機械性質影響之研究，國立臺灣科技大學機械工程學系碩士論文
[69] 王偉成 (2017)，電解液中添加 WS2 無機奈米顆粒對 AZ31鎂合金的微弧氧化陶瓷膜影響之研究，國立台灣科技大學機械工程學系碩士論文
[70] 蘇士銘 (2020)，不同溫度及道次等通道轉角擠製（ECAP）對 AZ61/Al2O3鎂基複合材料機械性質及腐蝕之影響，國立台灣科技大學機械工程學系碩士論文
[71] Valiev, R. Z., Islamgaliev, R. K., & Alexandrov, I. V. (2000), Bulk
nanostructured materials from severe plastic deformation. Progress in materials science, 45(2), Pages 103-189
[72] Huang, S.-J., Ho, C.-H., Feldman, Y., Tenne, R. (2016), Advanced AZ31 Mg alloy composites reinforced by WS2 nanotubes. Journal of Alloys and CompoundsVolume 654, Pages 15-22
[73] Huang, S.-J., Ali, A.N. (2019), Experimental investigations of effects of SiC contents and severe plastic deformation on the microstructure and mechanical properties of SiCp/AZ61 magnesium metal matrix composites. Journal of Materials Processing Technology 272, Pages 28-39
[74] Shahar, I., Hosaka, T., Yoshihara, S., & MacDonald, B. (2017), Mechanical and corrosion properties of AZ31 Mg alloy processed by Equal-Channel Angular Pressing and Aging. Procedia engineering. 184, 423-431
[75] 洪品森(2009)，鎂基複合材料的製備及其熱處理後機械性質之研究，國立中正大學機械工程學系碩士論文
[76] 周暾煜 (2016)，等徑轉角擠壓 (ECAP) 製程及添加物對 AZ 鎂合金儲氫性能之影響，國立台灣科技大學機械工程學系碩士論文
[77] 尤薇瑄(2020)，內部氫化製程對 Mg-5Y 合金機械性質影響之研究，國立台灣科技大學機械工程學系碩士論文
[78] 王芓淵(2021)，內部氫化製程對 Mg-10Y 合金機械性質與氫化行為影響之研究，國立台灣科技大學機械工程學系碩士論文
[79] X. Liua, S. Yin, Q. Lan, J. Xue, Q. Le, and Z. Zhang, “Investigation of the hydrogen states in magnesium alloys and their effects on mechanical properties”, Materials & Design 134, 2017, pp. 446-454.
[80] M. H. Korayem, R. Mahmudi, and W. J. Poole, “Enhanced properties of Mg-based nano-composites reinforced with Al2O3 nano-particles”, Materials science and engineering A 519, 2009, pp. 198-203.
[81] S. F. Hassan and M. Gupta, “Development of high performance magnesium nano-composites using nano-Al2O3 as reinforcement”, Materials science and engineering A 392, 2005, pp. 163-168.
[82] S. S. Zhou, K. K. Deng, J. C. Li, S. J. Shang, W. Liang, and J. F. Fan, “Effects of volume ratio on the microstructure and mechanical properties of particle reinforced magnesium matrix composite”, Materials and design 63, 2014, pp. 672-677.
[83] D. Setoyama, M. Ito, J. Matsunaga, H. Muta, M. Uno, and S. Yamanaka, “Mechanical properties of yttrium hydride”, Journal of alloys and compounds 394, 2005, pp. 207-210.
[84] Amit Bhaduri, “Mechanical Properties and Working of Metals and Alloys”, 2018, pp. 3-94.
[85] S. O. Ojediran, and O. Ajaja, "The Bailey-Orowan equation", Journal of materials science, vol. 23, pp. 4037-4040, 1998.