4384鋁合金為一接近共晶Si組成之Al-Si合金，有大量的晶出硬質相於α-Al基地中使4384鋁合金擁有高比強度、低熱脹係數、耐高溫及良好的耐磨耗性質，因此常運用於汽車工業上的活塞以及引擎汽缸體。目前常用之活塞製造方法為鑄造及鍛造，為了克服傳統製程之高孔隙率及製造成本高等問題，因此本研究導入了半固態製程。
半固態製程中之SIMA製程擁有設備成本低、製程穩定及球化率佳等優點，本研究所採用新型的SIMA製程，省去傳統製程中冷加工的步驟直接採用熱擠型導入足夠的應變能，加熱方式則改用鹽浴以及紅外線，研究之目的為探討4384鋁合金施以新型SIMA製程後，4384鋁合金微觀組織演變與特徵及沖蝕磨耗特性，並比較不同熱處理生成之SIMA材的差異性，以評估新型SIMA製程之應用性。
微觀組織分析結果顯示，單純熱擠型取代傳統冷壓縮加工段之新型SIMA製程，可確實製造出具有等軸球狀晶組織之半固態胚料，比較鹽浴以及紅外線加熱生成之SIMA材，發現可在較高操作溫度之紅外線熱處理其SIMA材擁有較高之液相率及球化率，其晶胞粗化速率也越高。
初始晶粒型態為等軸細晶之母材，於SIMA液相生成初期，液相無法完整穿刺(Penetrate)晶界，會發生Grain Coalescence，隨著持溫時間增加，液相逐漸完整包覆固相晶胞，晶胞會以Ostwald Ripening逐漸粗化，液相聚集成液相池以降低總表面能，最終形成球狀固相晶胞存在於液相基地之特徵組織。
材料沖蝕磨耗性質方面，4384鋁合金經由新型SIMA製程所得的硬質球狀晶晶界包覆軟質晶粒的組織，具有高於人工時效材的低角度顆粒沖蝕磨耗阻抗。硬質的球狀晶晶界可作為軟質晶粒於低角度沖蝕時的保護屏障，使材料提升低角度的耐顆粒磨耗性質。

4384 aluminum alloy with near-eutectic Si content is widely used in pistons and engines. The pistons are usually manufactured by means of casting or forging. In order to overcome the high porosity and high cost of traditional process, this study introduces semisolid process. The SIMA process is a semisolid process that is used to enhance high-temperature formability by generating fine and spheroidization grains. The most advantage is low cost, process stability and good spheroidization. This study adopts new type SIMA process, the hot extrusion was applied to induce sufficient strain energy to improve the defect of traditional SIMA process applied cold compression. Salt bath and Infrared are used to replace an air furnace for heating. The aim of this research is to investigate the effects of the new type SIMA process on the microstructure and particle erosion characteristics of 4384 aluminum alloy. Moreover, the differences of SIMA materials produced by different heating treatments were compared.
According to the results of the experiments, it could be fabricated semisolid billet with characteristic structure of equiaxed globular grain via the new type SIMA process applied simple hot extrusion instead of cold compression. The SIMA alloys heated by infrared with higher liquid fraction, good degree of spheroidization and higher grain coarsening rate than SIMA alloys heated by salt bath, because of the higher operating temperature of infrared heating.
The microstructure results show that the spheroidized grains form via new type SIMA process. Globular and surround by hard grain boundaries, creating a network structure. The erosion resistance of the SIMA-processed alloys is higher than that of artificial aged alloy at low impact angle. The high-hardness grain boundaries of SIMA-processed alloys can protect soft α-Al grains from being destroyed by erosion particle at oblique impact angle.

1.N. Wang, Z. Zhou, G. Lu, Microstructural evolution of 6061 alloy during isothermal heat treatment. Journal of Materials Science & Technology, 27(1): p.p. 8-14, 2011.
2.Z. Fan, Semisolid metal processing. International Materials Reviews, 47(2): p.p. 49-85, 2002.
3.E. Parshizfard, S. Shabestari, An investigation on the microstructural evolution and mechanical properties of A380 aluminum alloy during SIMA process. Journal of Alloys and Compounds, 509(40): p.p. 9654-9658, 2011.
4.Y. B. Song, K. T. Park, C. P. Hong, Recrystallization behavior of 7175 Al Alloy during modified strain-induced melt-activated (SIMA) process. Materials Transactions, 47(4): p.p. 1250-1256, 2006.
5.M. Paes and E. J. Zoqui, Semi-solid behavior of new Al-Si-Mg alloy for thixoforming. Materials Science and Engineering A, 406: p.p. 63-73, 2005.
6.E. H. Kottcamp, Jr., J. G. Simon, W. P. Koster, E. L. Langer, L. G. Thompson, Alloy Phase Diagrams. ASM Handbook, 1992.
7.R. Li, R. Li, Y. Zhao, L. He, C. Li, H. Guan, Z. Hu, Age-hardening behavior of cast Al-Si base alloy. Materials Letters, 58(15): p.p. 2096-2101, 2004.
8.M. M. Haque, M. Maleque, Effect of process variables on structure and properties of aluminium-silicon piston alloy. Journal of Materials Processing Technology, 77(1): p.p. 122-128, 1998.
9.J. Qiao, X. Liu, X. Liu, X. Bian, Relationship between microstructures and contents of Ca/P in near-eutectic Al-Si piston alloys. Materials Letters, 59(14): p.p. 1790-1794, 2005.
10.M. Zeren, The effect of heat-treatment on aluminum-based piston alloys. Materials and Design, 28(9): p.p. 2511-2517, 2007.
11.N. Terao, Beneficial influence of copper and manganese alloying elements on the mechanical properties of metallic composite materials based on the eutectic Al-5.7% Ni alloy. Journal of Materials Science, 20(11): p.p. 4021-4026, 1985.
12.M. M. Farag, M. C. Flemings, Structure and strength of Al, Cu-Al3Ni directionally solidified composites. Metallurgical Transactions A, 6(5): p.p. 1009-1015, 1975.
13.A. R. Farkoosh, M. Javidani, M. Hoseini, D. Larouche, M. Pekguleryuz, Phase formation in as-solidified and heat-treated Al-Si-Cu-Mg-Ni alloys: Thermodynamic assessment and experimental investigation for alloy design. Journal of Alloys and Compounds, 551: p.p. 596-606, 2013.
14.Y. Yang, Y. Li, W. Wu, D. Zhao, X. Liu, Evolution of nickel-rich phases in Al-Si-Cu-Ni-Mg piston alloys with different Cu additions. Materials and Design, 33: p.p. 220-225, 2012.
15.E. R. Wang, X. D. Hui, S. S. Wang, Y. F. Zhao, G. L. Chen, Improved mechanical properties in cast Al-Si alloys by combined alloying of Fe and Cu. Materials Science and Engineering: A, 527(29-30): p.p. 7878-7884, 2010.
16.Z. Ma, A. M. Samuel, F. H. Samuela, H. W. Doty, S. Valtierra, A study of tensile properties in Al-Si-Cu and Al-Si-Mg alloys: Effect of β-iron intermetallics and porosity. Materials Science and Engineering: A, 490(1-2): p.p. 36-51, 2008.
17.N. A. Belov, D. G. Eskin, N. N. Avxentieva, Constituent phase diagrams of the Al-Cu-Fe-Mg-Ni-Si system and their application to the analysis of aluminium piston alloys. Acta Materialia, 53(17): p.p. 4709-4722, 2005.
18.F. Toptan, A. C. Alves, I. Kerti, E. Ariza, L. A. Rocha, Corrosion and tribocorrosion behaviour of Al-Si-Cu-Mg alloy and its composites reinforced with B4C particles in 0.05M NaCl solution. Wear, 306(1-2): p.p. 27-35, 2013.
19.M. Warmuzek, Chemical composition of the Ni-containing intermetallic phases in the multicomponent Al alloys. Journal of Alloys and Compounds, 604: p.p. 245-252, 2014.
20.M. J. Starink, V. Abeels, P. V. Mourik, Lattice parameter and hardness variations resulting from precipitation and misfit accommodation in a particle-reinforced Al-Si-Cu-Mg alloy. Materials Science and Engineering: A, 163(1): p.p. 115-125, 1993.
21.J. E. Hatch, Aluminum properties and physical metallurgy. American Society for Metals, p.p. 175-193, 1984.
22.梁達嵐，「改良式SIMA法製備鎂合金半固態成形胚料之研究」，國立交通大學機械工程學系，碩士論文，6-37頁，2007。
23.K. P. Young, C. P. Kyonka, and J. A. Courtois, United States Patent 4415374, Nov.15, 1983.
24.江俊憲，「高矽含量噴覆成型過共晶鋁矽合金之固態成形性與半固態製程研究」，國立成功大學材料科學及工程學系，博士論文，85頁，2005。
25.E. Tzimas, A. Zavaliangos, A comparative characterization of near-equiaxed microstructures as produced by spray casting, magnetohydrodynamic casting and the stress induced, melt activated process. Materials Science and Engineering: A, 289(1): p.p. 217-227, 2000.
26.E. Glickman, M. Nathan, On the kinetic mechanism of grain boundary wetting in metals. Journal of Applied Physics, 85(6): p.p. 3185-3191, 1999.
27.C. W. Lin, F. Y. Hung, T. S. Lui, L. H. Chen, Structural characteristics and particle erosion resistance of SIMA-processed Al-Mg-Si alloy. Materials Transactions, 57(2): p.p. 135-142, 2016.
28.E. Tzimas, A. Zavaliangos, Evolution of near-equiaxed microstructure in the semisolid state. Materials Science and Engineering: A, 289(1): p.p. 228-240, 2000.
29.F. Akhlaghil, A. H. S. Farhood, Characterization of globular microstructure in NMS processed aluminum A356 alloy: the role of casting size. Advenced Mateials Researchs, 264-265: p.p. 1868-1877, 2010.
30.M. Emamy, A. Razaghian, M. Karshenas, The effect of strain-induced melt activation process on the microstructure and mechanical properties of Ti-refined A6070 Al alloy. Materilas and Design, 46: p.p. 824-836, 2013.
31.K. S. Lee, S. Kim, K. R. Lim, S. H. Hing, K. B. Kim, Y. S. Na, Crystallization, High temperature defroemtaion behavior and solid-to-dolid formability of a Ti-based bulk metallic glass within supercooled liquid region. Journal of Alloys and Compounds, 663: p.p. 270-278, 2016.
32.H. Tang, Z. Cheng, J. Liu, X. Ma, Preparation of a high strength Al-Cu-Mg alloy by mechanical alloying and press-forming, Materials Science and Engineering A, 550: p.p. 51-54, 2012.
33.Z. Wang, Z. Ji, M. Hu, H. Xu, Evolution of the semi-solid microstructure of ADC12 alloy in a modified SIMA process. Materials Characterization, 62(10): p.p. 925-930, 2011.
34.G. Yan, S. Zhao, S. Ma, H. Shou, Microstructural evolution of A356. 2 alloy prepared by the SIMA process. Materials Characterization, 69: p.p. 45-51, 2012.
35.A. Bolouri, M. Shahmiri, C. G. Kang, Coarsening of equiaxed microstructure in the semisolid state of aluminum 7075 alloy through SIMA processing. Journal of Materials Science, 47(8): p.p. 3544-3553, 2012.
36.A. Bolouri, M. Shahmiri, C. Kang, Study on the effects of the compression ratio and mushy zone heating on the thixotropic microstructure of AA 7075 aluminum alloy via SIMA process. Journal of Alloys and Compounds, 509(2): p.p. 402-408, 2011.
37.Y. B. Song, K.T. Park, C. P. Hong, Grain refinement of 6061 Al alloy by the modified strain-induced melt-activated (SIMA) process for semi-solid processing. Solid State Phenomena, 119: p.p. 311-314, 2007.
38.侯彥羽，「改良式SIMA製程之累積應變量及鹽浴時間對6068鋁合金微觀組織及拉伸性質之影響」，國立成功大學材料科學及工程學系，碩士論文，56-58頁，2013。
39.L. Zhang, Y. Liu, Z. Cao, Y. Zhang, Q. Zhang, Effects of isothermal process parameters on the microstructure of semisolid AZ91D alloy produced by SIMA. Journal of Materials Processing Technology, 209(2): p.p. 792-797, 2009.
40.Z. Ji, M. Hu, S. Sugiyama, J. Yanagimoto, Formation process of AZ31B semi-solid microstructures through strain-induced melt activation method. Materials Characterization, 59(7): p.p. 905-911, 2008.
41.Q. Qin, Y. Zhao, K. Xiu, W. Zhou, Y. Liang, Microstructure evolution of in situ Mg2Si/Al-Si-Cu composite in semisolid remelting processing. Materials Science and Engineering: A, 407(1): p.p. 196-200, 2005.
42.J. Wang, P. Lu, H. Wang, J. Liu, Q. Jiang, Semisolid microstructure evolution of the predeformed AZ91D alloy during heat treatment. Journal of Alloys and Compounds, 395(1): p.p. 108-112, 2005.
43.H. V. Atkinson, D. Liu, Coarsening rate of microstructure in semi-solid aluminium alloys. Transactions of Nonferrous Metals Society of China, 20(9): p.p. 1672-1676, 2010.
44.S. Hardy, P. Voorhees, Ostwald ripening in a system with a high volume fraction of coarsening phase. Metallurgical Transactions A, 19(11): p.p. 2713-2721, 1988.
45.C. B. Alcock, Thermochemical Processes: Principles and Models. Reed Educational and Professional Publishing Ltd., p.p. 209-213, 2001.
46.劉弘仁，「紅外線在狹縫式塗佈乾燥上的應用」，國立清華大學化學工程學系，碩士論文，1-5頁，2000。
47.陳仕穎，「利用銀基及鋁基填料紅外線硬銲接合鈦鋁介金屬之研究」，國立臺灣大學材料科學與工程學系，碩士論文，2012。
48.M. Hernández, M. González, Synthesis of resins as alpha-alumina precursors by the Pechini method using microwave and infrared heating. Journal of the European Ceramic Society, 22(16): p.p. 2861-2868, 2002.
49.E. Rabinowicz, Friction and wear of materials. 1965.
50.Z. Gahe, K. H., Microstructure and wear of materials. Elsevier, 10: 1987.
51.J. Q. Su, T. W. Nelson, C. J. Sterling, Microstructure evolution during FSW/FSP of high strength aluminum alloys. Materials Science and Engineering: A, 405(1): p.p. 277-286, 2005.
52.I. Finnie, Some reflections on the past and future of erosion. Wear, 186: p.p. 1-10, 1995.
53.K. G. Budinski, Surface engineering for wear resistance. Prentice Hall, 1988.
54.J. T. DeMasi Marcin, D. K. Gupta, Protective coatings in the gas turbine engine. Surface and Coatings Technology, 68: p.p. 1-9, 1994.
55.Y. Oka, H. Ohnogi, T. Hosokawa, M. Matsumura, The impact angle dependence of erosion damage caused by solid particle impact. Wear, 203: p.p. 573-579, 1997.
56.W. F. William, Erosion: Prevention and useful applications. ASTM Internal, 664, 1979.
57.I. Hussainova, Microstructure and erosive wear in ceramic-based composites. Wear, 258(1): p.p. 357-365, 2005.
58.I. Hussainova, Some aspects of solid particle erosion of cermets. Tribology International, 34(2): p.p. 89-93, 2001.
59.I. Finnie, Erosion of surfaces by solid particles. Wear, 3(2): p.p. 87-103, 1960.
60.J. G. A. Bitter, A study of erosion phenomena: part I. Wear, 6: p.p. 5-21, 1963.
61.J. G. A. Bitter, A study of erosion phenomena: part II. Wear, 6: p.p. 169-190, 1963.
62.G. A. Sargent, P. K. Mehrotra, H. Conra, Erosion: Prevention and useful applications, ASTM STP 664, W.F. Adler ed., ASTM, p.p. 77-100, 1979.
63.A. V. Levy, The Role of Plasticity in Erosion. in Proc. 5th Int. Conf.Erosion by Solid and Liquid Impact. Cambridge, 39: p.p. 1-10, 1979.
64.洪飛義，「矽含量及基地組織對球墨鑄鐵顆粒沖蝕磨耗行為之影響」，國立成功大學材料科學及工程學系，博士論文，2002。
65.F. Y. Hung, L. H. Chen, T. S. Lui, A study on erosion of upper bainitic ADI and PDI. Wear, 260(9): p.p. 1003-1012, 2006.
66.J. E. Hatch, Aluminum properties and physical metallurgy. American Society for Metals, p.p. 50, 1984.
67.T. Christman, P. G. Shewmon, Erosion of a strong aluminum alloy. Wear, 52(1): p.p. 57-70, 1979.
68.Y. Shin, G. Sargent, H. Conrad, Effects of microstructure on the erosion of Al-Si alloys ny solid particles. Metallurgical Transactions A, 18(3): p.p. 437-450, 1987.
69.劉中偉，「片狀石墨鑄鐵與鋁-系矽合金之矽砂沖蝕磨耗特性研究」，國立成功大學材料科學及工程學系，博士論文，1998。
70.J. Tu, J. Pan, M. Matsumura, H. Fukunaga, The solid particle erosion behavior of Al18B4O33 whisker-reinforced AC4C al alloy matrix composites. Wear, 223(1): p.p. 22-30, 1998.
71.林啟航，「4384 Al-Si-Cu-Ni-Mg鋁合金切削斷屑性之時效處理效應」，國立成功大學材料科學及工程學系，碩士論文，25頁，2011。
72.N. A. Belov, D. G. Eskin, N. N. Avxentieva, Constituent phase diagrams of the Al-Cu-Fe-Mg-Ni-Si system and their application to the analysis of aluminium piston alloys. Acta Materialia, 53(17): p.p. 4709-4722, 2005.
73.林修群，「固溶化處理對旋鍛4384鋁合金微觀組織與拉伸性質之影響」，國立成功大學材料科學及工程學系，碩士論文，21-23頁，2015。.
74.P. Y. Zhu, Q. Y. Lin, T. X. Hou, Spheroidization of eutectic silicon in Al-Si Alloy, AFS Transactions, 93: p.p. 609-614, 1985.
75.H. Kezhun, Y. Fuxiao, Z. Dazhi, Z. Liang, Microstructural evolution of direct chill cast Al-15.5Si-4Cu-1Mg-1Ni-0.5Cr alloy during solution treatment. Research and Development, 8(3): p.p. 264-268, 2011.
76.Y. Yang, S. Y. Zhong, Z. Chen, M. Wang, N. Ma, H. Wang, Effect of Cr content and heat-treatment on the high temperature strength of eutectic Al-Si alloys. Journal of Alloys and Compounds, 647: p.p. 63-69, 2015.
77.Y. Sui, Q. Wang, G. Wang, T. Liu, Effects of Sr content on the microstructure and mechanical properties of cast Al-12Si-4Cu-2Ni-0.8 Mg alloys. Journal of Alloys and Compounds, 622: p.p. 572-579, 2015.
78.Y. Sui, Q. Wang, T. Liu, B. Ye, H. Jiang, W. Ding, Influence of Gd content on microstructure and mechanical properties of cast Al-12Si-4Cu-2Ni-0.8 Mg alloys. Journal of Alloys and Compounds, 644: p.p. 228-235, 2015.