臺灣博碩士論文加值系統

本論文研究主要探討Ti-6Al-4V鍛造製程參數對其特性及顯微組織之影響，尤其著重在鍛造製程參數與金相組織及硬度測量結果的關聯性分析。基於此，內容分為兩個主要的方向：一為鍛造表面之a-case的生成及其厚度和硬度的量測，二為不同製程參數下所得到之金相與硬度之分佈。
在a-case的相關研究結果顯示，在a-case區域內的氧原子濃度隨距離鍛造表面深度的增加而呈現遞減的趨勢，且其濃度皆比素材原始濃度高。這證實了a-case之生成和鍛造表面之氧的擴散作用有關。此外，藉由不同製程條件下所產生之a-case的氧原子成份分析指出，三個道次的鍛造製程設定將比五個道次的設定更能加速氧的擴散作用，並經由a-case厚度的量測與硬度的測量，證實了在此情形下，將導致a-case的厚度增大，並使距離表面相同深度的位置擁有較高的硬度。
歸納製程參數對整體硬度分佈的影響，發現在Tb 上方40℃的範圍中進行鍛造時，不管鍛打道次的設定如何，只要處於高應變的狀態下，則溫度的差異並不會造成硬度的不同。但隨著鍛造溫度區間的升高，硬度值會快速地下降。在硬度的測量結果亦證實，高應變區將擁有較佳的硬度穩定性，這說明了高變形區的劇烈塑性流動將促進材料的均質化。此外，經由文獻和金相觀察的綜合整理，在此也歸納出三個溫度區間的金相演化機構，包括：在單相b區鍛造、在雙相a+b區鍛造以及變形在b區開始，而在a+b區結束。其所演化而成的組織與特性皆有不同。此外，藉由演化機構及現場所搜集的製程參數，本文進一步修正了製程參數表。
整體而言，本文歸納了Ti-6Al-4V基本的鍛造特性，以金相觀察及儀器量測的結果，建立了製程-組織-性質的初步關聯性。

In this study, the correlation of working parameters and characteristics as well as microstructure evolutions of Ti-6Al-4V by forging process was investigated. There are two main concerns: (1) The evolution and mechanism of a-case formation on the forging surface. The thickness and hardness distribution of a-case was measured. (2) The correlation of microstructure and hardness of specimens relates to the working parameters.
Study result on a-case formation shows that oxygen concentration is highest on forging surface and decreases with the increasing distance from the forging surface. This proves the formation of a-case is controlled by the diffusion mechanism. Furthermore, the three-forging-pass-finished specimens have stronger diffusion effect than the five-forging-pass-finished specimens. As a result, a thicker a-case and higher hardness depth were formed by there-forging-pass-finished specimens as compared to the five-pass-forging-finished ones.
Summarized results from the relationships of working parameters and overall hardness showed that if forging is performed on temperature 40℃ above Tb in addition to high strain, whatever forging pass was set, temperature difference will not result significant hardness change. However, if forging temperature is much higher than Tb , hardness will decrease rapidly. The results of hardness test demonstrate that the region with high strain has better hardness stability. This means that severe plastic flow in material will promote the homogeneity of Ti-6Al-4V. Moreover, basing on our literatures survey and microstructure observations, three different microstructure evolution mechanisms were classified according to forging temperature: (1) Forging began and completed in single b phase region. (2) Forging began and completed in a＋b region. (3) Forging Began in b region and completed in a＋b region. Typical microstructures and properties are thus developed. Basing on this relationship, the working parameters were further modified according to the developed microstructure.
As a whole, basic forging characteristics of Ti-6Al-4V were summarized in this thesis. Through microstructure observation and measurement results, primary process-microstructure-property correlation of Ti-6Al-4V was constructed.

中文摘要I
英文摘要II
誌謝III
總目錄IV
圖目錄VII
表目錄IX
符號說明X
第一章 前言1
第二章 理論說明2
2.1 a/b型鈦合金Ti-6Al-4V2
2.1.1鈦合金介紹2
2.1.2 組織型態及名稱定義3
2.2 a/b型鈦合金熱作製程5
2.2.1 初鍛與再結晶退火5
2.2.2 二次製程與後續熱處理6
2.3 球化理論7
2.3.1 初始晶界及剪切帶的形成7
2.3.2 b相的透入8
2.4 a-case的介紹9
第三章 文獻回顧10
第四章 實驗方法與步驟13
4.1 實驗流程13
4.2 實驗儀器及設備13
4.3 實驗材料14
4.4 金相試件製備與顯微分析15
4.4.1 金相試件製備15
4.4.2 金相觀察15
4.5 a-case厚度的定量量測15
4.6硬度量測15
4.7模擬結果的採用16
第五章 實驗結果與討論17
5.1 製程參數對a-case的影響分析17
5.1.1 實際製程參數的修正17
5.1.2 冷卻速率對a-case的影響分析19
5.1.3 a-case區域成份分析20
5.1.4 a-case厚度與鍛造製程的關聯性分析22
5.1.5 球化作用對a-case的影響分析23
5.1.6 a-case區域的硬度與鍛造製程關聯性分析25
5.1.6.1 No.1及No.2表面區域硬度與鍛造製程參數的關
聯性分析25
5.1.6.2 其他試件a-case區域硬度與鍛造製程參數的關聯
性26
5.2 鍛造製程參數對金相組織及硬度影響分析27
5.2.1鍛造製程參數與金相演化的關係27
5.2.1.1金相分佈情況27
5.2.1.2 不同鍛造溫度區間的金相演化關係28
5.2.1.2.1 在單相b區鍛造的金相演化關係29
5.2.1.2.2 在雙相a+b區鍛造的金相演化關係30
5.2.1.2.3 變形在b區開始，而在a+b區結束31
5.2.2 鍛造製程參數與硬度之關聯性32
5.2.2.1 硬度與鍛造溫度之關聯性分析32
5.2.2.2 硬度與等效應變之關聯性分析34
第六章 結論35
6.1 製程參數對a-case的影響分析35
6.2 鍛造製程參數對金相顯微組織及硬度影響分析36
第七章 未來研究方向38
第八章 參考文獻40

1. C. Frueh, D. R. Poirier, and M. C. Marguire, "The Effect of Silica-Comtaining Binders on the Titanium/Face Coat Reaction", Metallurgical and Materials Transactions B, Vol. 28B, pp. 919-926. 1997.
2. K. H. Koopman, "Effect of The Oxidation Behavior of Titanium Alloy Ti-6Al-4V", Welding Research Council Progress Reports, Vol. 35, (9), pp.22-30, 1980.
3. S. L. Semiatin, V. Seetharaman, and I.Weiss, "The Thermomechanical Processing of Alpha/Beta Titanium Alloys", JOM, 49, (6), pp. 33-39, 68, 1997.
4. H. Margolin and P. Cohen, "Titanium''80: Science and Technology", ed. H. Kimura and O.Izumi (Warrendale, PA: TMS, 1980), pp. 1555-1561.
5. I. Weiss et al., "Modification of Alpha Morphology in Ti-6Al-4V by Thermomechnical Processing", Metall. Trans. A, Vol. 17A, pp. 1935-1947, 1986.
6. H. Margolin and P. Cohen, "Titanium''80: Science and Technology", A. Tanabe ed al. (Warrendale, PA: TMS, 1980), pp. 937-945.
7. J. G. Malcor, F. Montheillet, and B. Champin, "Titanium: Science and Technology", ed. G. Luetjering, U. Zwicker, and W. Bunk (Oberursel, Germany: DGM, 1985), pp. 1495-1502.
8. H. Margolin and P. Cohen, "Titanium''80: Science and Technology", ed. H. Kimura and O.Izumi (Warrendale, PA: TMS, 1980), pp.2991-2997.
9. J. G. Malcor, F. Montheillet, and B. Champin, "Titanium: Science and Technology", I.Weiss et al. (Oberursel, Germany: DGM, 1985), pp. 1503-1510.
10. G. Welsch et al., "Sixth World Conference on Titanium", ed. P. Lacombe, R. Tricot, and G. Beranger (Les Ulis Cedex, France: SF2M, 1988), pp. 1289-1293.
11. Mattew J. Donachie, Jr., ed. "Titanium, A Technical Guide", 2nd Edition, ASM International, 1989.
12. E. A.鮑利索娃等著, 陳石卿譯, "鈦合金金相學", 新華書店北京發行所, 1986.
13. J. F. Uginet et al., "Titanium''92: Science and Technology", ed. F. H. Froes and I. L. Caplan (Warrendale, PA: TMS, 1993), pp. 463-471.
14. T. Sheppard and J. Norley, "Deformation Characteristics of Ti-6Al-4V", Mater. Sci. Techn. , Vol.4, pp. 903-908,1988.
15. S. L. Semiatin, J. F. Thomas, Jr., and P. Daras, "Processing-Microstructure Relationships for Ti-6Al-2Sn-4Zr-2Mo-0.1Si", Metall. Trans. A, Vol. 14A, pp. 1363-2374.
16. S. M. L. Sastry et al., "Superplastic Forming Charaterization of Titanium Alloys", J. Metals, Vol. 35 (1), pp. 48-53, 1983.
17. H. M. Flower, "Microstructural Development in Relation to Hot Working of Titanium Alloys", Metal. Sci. Techn., Vol. 6, pp.1082-1092.1990.
18. H. Margolin and P. Cohen, "Titanium''80, 4th International Conference on Titanium", Kyoto, Japan, pp. 1555-1561, 1980.
19. 林文樹, 蔡振輝, 林瑞進, 張景堯, 金福德等著, "材料手冊:鈦及鈦合金", 中國材料科學學會, 1983.
20. H. Margolin and L. Rosenberg, "Titanium''80: Science and Technology", ed. H. Kimura and O. Izumi (Warrendale, PA, The Metallurgical Society of AIME, 1980), pp. 1637-1642.
21. R. G. Broadwell and M. L. Greenlee, "The Mechanical Property and Microstructural Characteristics of Alpha-Beta Processed Super Alpha Titanium Alloys Containing Silicon", Special Report No.24, Titanium Metals Corporation of America Application Development Center, NJ, 1966.
22. G. R. Yoder, L. A. Cooley, and T. W. Crooker, ?rd Structure, Structural Dynamics and Materials Conference", New Orlean, LA, pp. 132-136, 1982.
23. D. Eylon, M. E. Rosenblum, and Fujishiro, "Titanium''80, 4th International Conference on Titanium", Kyoto, Japan, pp. 1845-1854, 1980.
24. S. M. Sastry, P. S. Pao, and K. K. Sankaran, "Titanium''80, 4th International Conference on Titanium", Kyoto, Japan, pp. 873-886, 1980.
25. F. H. Froes, J. C. Chesnutt, R. G. Berryman, G. R. Keller, and W. T. Highberger, ?th National SAMPE Technical Conference", Kiamesha, NY, pp. 511-523, 1978.
26. 王凱宏, "鈦合金四面精鍛製程參數研究", 國立成功大學機械研究所碩士論文,1998.
27. 王凱宏, 張家銘, "榮剛重工股份有限公司合作研究計劃-鈦合金Ti-6Al-4V四面精鍛製程模擬分析技術（一）", 不公開文件, 1998.
28. 王凱宏, 張家銘, "榮剛重工股份有限公司合作研究計劃-鈦合金Ti-6Al-4V四面精鍛製程模擬分析技術（二）", 不公開文件, 1999.
29. 李榮顯, 林煥章, "鋁合金熱擠伸之製程參數與再結晶行為關係之研究", Vol. 36, (1), 1992.
30. 江照雄, "熱處理對Ti-6Al-4V顯微組織特性影響之分析研究", 國立成功大學機械工程學系碩士論文, 1990.
31. Metals Handbook 5th Edition, Vol. 9, "Metallography and Microstructure", America Society for Metals, Metals Park, 1992.