鎳基材料與大部分的材料一樣，有非常多的應用，但也有其限制。鎳鋁材料是已經廣泛應用且技術成熟的其中一種合金材料，但是仍然有兩大限制：室溫之下的延展性短缺以及高溫之下的抗潛變強度尚須加強，而探討延展性如何變化以及驗證其他相關性質即是本文主要目的。

本研究中使用的三種材料皆以鎳金屬為基材，有等計量比鎳鋁合金和分別添加鐵0.25%以及1%的鎳鋁合金，添加鐵元素之後會對材料的微結構產生變化，進而改變巨觀的機械性質，連結微結構與機械性質之間的關係，為此實驗設計的出發點。本研究分別使用硬度測試儀以及同步輻射X光繞射，硬度測試儀與一般機械測試原理相似，可以了解材料的機械性質，同步輻射則提供了穿透式的X光繞射圖譜，分析可得材料內部的訊息。材料在進行兩個實驗之前，皆會經過研磨以及拋光的處理，之後再進行硬度測試做應變，在材料上產生應變，在同步輻射X光繞射實驗時，透過瞄準該應變區域，達到比較應變前後的差異。
經過兩種實驗分析後的結果，對鎳鋁合金而言，添加鐵元素，會使鎳鋁合金有軟化的作用，但是材料的性質並不會隨添加鐵元素之量增加而無限改善，鐵元素添加到一定的量之後，材料的性質即達到最佳化效果，所以推測材料內部已經受到析出或組成的影響，並進一步造成機械性質的改變。從同步輻射的繞射結果也證明了隨著鐵元素含量的增加，會伴隨著塑性變形區的擴張，但是同樣添加鐵元素的量達到一定值之後，材料性質會停止變化並開始下降。此研究中使用的分析掃描測試方法，對塑性型變區有辨識的能力，並更具有客觀性。

Like most other intermetallics, unalloyed Nickel Aluminide systems have many important applications but also lack the ductility at room temperature. In this study, three kinds of Nickel Aluminide alloys were prepared with different Fe content (0, 0.25, and 1 atomic percentage respectively). We applied indentation to investigate the mechanical performance of the alloys. The deformed areas around the indentation are investigated using the synchrotron x-ray diffraction to map the microstructure distribution of the alloys. After mapping a five by five points, each point aparts 100μm, the distribution of the lattice-strain, diffraction intensity, and peak width of different phases are revealed.

參 考 文 獻
1. Callister WD, Rethwisch DG. Materials science and engineering: an introduction. 2007.
2. Cutler CP. nickel nickel everywhere. Materials World. 1998.
3. Darolia R. NiAl alloys for high-temperature structural applications. JOM. 1991;43(3):44-49.
4. Ishida K, Kainuma R, Ueno N, Nishizawa T. Ductility enhancement in NiAl (B2)-base alloys by microstructural control. Metallurgical and materials Transactions A. 1991;22(2):441-446.
5. Darolia R, Lahrman D, Field R. The effect of iron, gallium and molybdenum on the room temperature tensile ductility of NiAl. Scripta Metallurgica et Materialia;(United States). 1992;26(7).
6. Baker I, Nagpal P, Liu F, Munroe P. The effect of grain size on the yield strength of FeAl and NiAl. Acta metallurgica et materialia. 1991;39(7):1637-1644.
7. Schneibel J, Darolia R, Lahrman D, Schmauder S. Fracture morphology of NiAl single crystals tested in tension. Metallurgical and Materials Transactions A. 1993;24(6):1363-1371.
8. Miracle D. Overview No. 104 the physical and mechanical properties of NiAl. Acta Metallurgica et Materialia. 1993;41(3):649-684.
9. Pike L, Chang Y, Liu C. Solid-solution hardening and softening by Fe additions to NiAl. Intermetallics. 1997;5(8):601-608.
10. Fine M, Vaynman S, Isheim D, Chung Y-W, Bhat S, Hahin C. A New Paradigm for Designing High-Fracture-Energy Steels. Metallurgical and Materials Transactions A. 2010;41(13):3318-3325.
11. Teng Z, Miller MK, Ghosh G, et al. Characterization of nanoscale NiAl-type precipitates in a ferritic steel by electron microscopy and atom probe tomography. Scripta Materialia. 2010;63(1):61-64.
12. Schulson E, Barker D. A brittle to ductile transition in NiAl of a critical grain size. Scripta metallurgica. 1983;17(4):519-522.
13. Nagpal P, Baker I. The effect of grain size on the room-temperature ductility of NiAl. Scripta Metallurgica;(United States). 1990;24(12).
14. Xu S, Tyson W. Nickel in structural alloys. Canadian metallurgical quarterly. 2002;41(2):219-230.
15. Shinagawa K, Omori T, Oikawa K, Kainuma R, Ishida K. Ductility enhancement by boron addition in Co–Al–W high-temperature alloys. Scripta Materialia. 2009;61(6):612-615.
16. Sheng L, Zhang W, Guo J, Yang F, Liang Y, Ye H. Effect of Au addition on the microstructure and mechanical properties of NiAl intermetallic compound. Intermetallics. 2010;18(4):740-744.
17. Ren W, Guo J, Li G, Zhou J. Effect of Nd on microstructure and mechanical properties of NiAl-based intermetallic alloy. Materials Letters. 2003;57(8):1374-1379.
18. Aghajanian MK, Macmillan N, Kennedy CR, Luszcz S, Roy R. Properties and microstructures of Lanxide® Al2O3-Al ceramic composite materials. Journal of materials Science. 1989;24(2):658-670.
19. Cotton J, Noebe R, Kaufman M. The effects of chromium on NiAl intermetallic alloys: Part I. microstructures and mechanical properties. Intermetallics. 1993;1(1):3-20.
20. Tuan W, Brook R. The toughening of alumina with nickel inclusions. Journal of the European Ceramic Society. 1990;6(1):31-37.
21. Chou W, Tuan W. Toughening and strengthening of alumina with silver inclusions. Journal of the European Ceramic Society. 1995;15(4):291-295.
22. Oh S-T, Sekino T, Niihara K. Fabrication and mechanical properties of 5 vol% copper dispersed alumina nanocomposite. Journal of the European Ceramic Society. 1998;18(1):31-37.
23. Trusty P, Yeomans J. The toughening of alumina with iron: effects of iron distribution on fracture toughness. Journal of the European Ceramic Society. 1997;17(4):495-504.
24. Tuan W. Toughening alumina with nickel aluminide inclusions. Journal of the European ceramic society. 2000;20(7):895-899.
25. Tabor D. The Hardness of Metals. 2000.
26. Will G. Powder Diffraction: The Rietveld method and the two-stage method: Springer; 2006.
27. Liu Z, Guo J, Zhou L, Hu Z, Umemoto M. Mechanical alloying synthesis and structural characterization of ternary Ni-Al-Fe alloys. Journal of materials science. 1997;32(18):4857-4864.
28. Ahn J-H, Kwon D. Derivation of plastic stress-strain relationship from ball indentations: Examination of strain definition and pileup effect. JOURNAL OF MATERIALS RESEARCH-PITTSBURGH-. 2001;16(11):3170-3178.
29. Giannakopoulos A, Larsson P-L, Vestergaard R. Analysis of Vickers indentation. International journal of Solids and Structures. 1994;31(19):2679-2708.
30. Weihs T, Zinoviev V, Viens D, Schulson E. The strength, hardness and ductility of Ni< sub> 3</sub> Al with and without boron. Acta Metallurgica. 1987;35(5):1109-1118.
31. Hughes G, Smith S, Pande C, Johnson H, Armstrong R. Hall-Petch strengthening for the microhardness of twelve nanometer grain diameter electrodeposited nickel. Scripta metallurgica. 1986;20(1):93-97.
32. Zeng K, Chiu C. An analysis of load–penetration curves from instrumented indentation. Acta materialia. 2001;49(17):3539-3551.
33. Pike L, Chang Y, Liu C. Point defect concentrations and hardening in binary B2 intermetallics. Acta materialia. 1997;45(9):3709-3719.
34. Westbrook JH. Intermetallic compounds: Their past and promise. Metallurgical Transactions A. 1977;8(9):1327-1360.