Temperature Effects on the High-Temperature Corrosion Behavior of High-Strength Titanium-Based Alloys

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基本資料

Project title

Code/計畫編號

NSC97-2221-E019-004

Translated Name/計畫中文名

溫度效應對高強度鈦合金顯微組織、機械性質及氧化行為之影響研究---溫度效應對高強度鈦合金高溫腐蝕行為之研究

Project Coordinator/計畫主持人

Wu Kai

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Optoelectronics and Materials Technology

Website

https://www.grb.gov.tw/search/planDetail?id=1661685

Year

2008

Start date/計畫起

01-08-2008

Expected Completion/計畫迄

31-07-2009

Bugetid/研究經費

969千元

ResearchField/研究領域

材料科技

本計畫為【溫度效應對高強度鈦合金顯微組織、機械性質及氧化行為之影響研究】整合型計畫之子計劃二，擬以三年為一期，主要探討『溫度效應對高強度鈦合金高溫腐蝕行為之研究』，茲將各年度之研究要點分述如下： (1) 第一年度將評估溫度效應對α−β型雙相鈦合金（選定Ti-6Al-6V-2Sn合金，以下簡稱Ti-6-6-2）在含純氧、空氣（含有/無水蒸氣）及氬/氧混合氣、披覆Na2SO4/NaCl（不同配比之熱腐蝕源）等條件下高溫腐蝕的影響，同時配合適當的表面改質方式（如：鍍鎳滲鋁/鉻、熔融鹽電解滲鋁/鉻、奈米鉻鋁鍍層、或預氧化處理），以期提升Ti-6-6-2的抗蝕能力；預期的溫度效應將細分為恆溫（範圍在600-900oC）及熱循環（即多次由室溫到高溫再降溫之方式）兩大類，藉以探討不同溫度效應及表面改質下鈦合金之腐蝕動力學及反應機構。全程實驗是在高靈敏度之熱重分析儀(TGA)或石英彈簧(管式高溫爐)中進行，以連續監測試片經腐蝕反應後所得的相對重量變化量，經轉換並計算合金之腐蝕動力學數據；同時，藉由白金指標測試可判斷腐蝕反應的主要機制，並輔以X-光繞射(XRD)、光學金相(OM)、掃描式電鏡(SEM)、電子微探儀(EPMA)、電子能譜儀(AES)及穿透式電鏡(TEM)之分析，以瞭解溫度效應下Ti-6-6-2的腐蝕物相組成、成分分布及反應界面之差異性。 (2) 第二年度擬評估溫度效應對高強度β型鈦合金（選定Ti-15V-3Cr-3Al-3Sn合金，以下簡稱Ti-15-3）在第一年度所建立的不同腐蝕環境及表面改質方式下高溫腐蝕的影響（方法同第一年），同時也將配合其他子計畫之第一年研究成果及經驗（如：子計畫一及四在顯微結構變化及晶粒細化，以及子計畫三銲接之晶粒粗化），來探討晶粒細化及粗化對Ti-6-6-2高溫腐蝕之差異性，其結果將與第一年度之成果相互比較，瞭解合金元素及顯微組織對α−β型及β型鈦合金之抗蝕能力的影響，逐步建構鈦合金高溫腐蝕實驗數據資料庫。 (3)第三年度擬將彙整前二年本子計劃之研究成果，並配合其他子計畫在二年內之研究成果及經驗（如：子計畫一及四在顯微結構變化及晶粒細化，以及子計畫三銲接之晶粒粗化），來評估溫度效應對晶粒細化及粗化之Ti-15-3在前兩年度所建立的不同腐蝕環境及表面改質方式下高溫腐蝕的影響（方法同第一年），同時，也將其結果將與前兩年度之成果相互比較，瞭解合金元素及顯微組織對β型鈦合金之抗蝕能力的影響，完整建立鈦合金的高溫腐蝕實驗數據；在執行期間，各主持人透過定期與其他子計畫之心得交換，以期找出最佳的合金材質、表面改質組成及顯微組織參數，建立整體的鈦合金之應用資料庫，一方面可將研究成果發表於國際知名期刊，以彰顯國內研究的知名度，另一方面將研究成果直接提供相關業界運用，促進鈦合金發展之應用價值。The research proposal of ""Temperature effects on the high-temperature corrosion behavior of high-strength titanium-based alloys"" is proposed. This is a part of the 3-year group-proposal of ""Temperature effects on the microstructure, mechanical properties, and oxidation behavior of high-strength titanium-based alloys” (in Proposal Part II). The main subjects of this research are described yearly as follows: (1) In the first year, the effects of temperature on the high-temperature corrosion of a α-β-type high-strength Ti-based alloy, Ti-6Al-6V-2Sn (Ti-6-6-2) are evaluated over the temperature range of 600-900oC in various O2-containing environments (containing pure oxygen, air with or without water vapor, and Ar-O2 mixed gases) and in air with the samples deposited by various ratios of Na2SO4/NaCl mixed salts). The alloys with proper surface-modifications (i.e. containing Ni-plating plus Al/Cr dipping, Al/Cr-molten-salt electro-deposition, and Cr-Al nano-depositions) were also investigated in order to enhance the corrosion resistance, as compared to those of the original alloy-substrate. Both isothermal- and cyclic-oxidation conditions will be explored to study the difference of the possible corrosion kinetics and reaction mechanisms of the alloys with or without surface-modifications. The corrosion tests of samples are performed by continuously measuring mass-change data through thermo-gravimetric analyzer (TGA) or quartz springs in the tube furnace. The corrosion data are converted and compared to scale thickness obtained metallurgically. Pt-marker studies are performed to determine reaction mechanisms of the alloys, and X-ray diffraction (XRD) and microstructural analyses (including OM, SEM, EPMA, AES, and TEM) are further to analyze the phase constitution and spatial distribution of the scales as well as the characterization of the scale/substrate interface. (2) In the second year, the effects of temperature on the corrosion behavior of a β-type high-strength Ti-based alloy, Ti-15V-3Cr-3Al-3Sn (Ti-15-3) will be evaluated in the same procedure of (1). This is done to establish the fundamental database for the high-temperature corrosion behaviors of high-strength Ti-based alloys. In addition, the difference between grain-refining and -coarsening Ti-6-6-2 based on the results of other sub-proposals in the first year (such as the microstructure refining and grain coarsening obtained in Part I/IV and III, respectively), will also be evaluated, and the results will be compared to those obtained in the first year. The roles of alloying elements and microstructural characterization on the corrosion resistance of the two Ti-based alloys will be discussed in order to build up the database for high-temperature corrosion and prevention. (3) In the third year, based on the results of other sub-proposals in the first and second years (as similar to those indicated in (2)), the temperature and grain-size effects of Ti-15-3 will also be evaluated, as the same procedure of (1). The results of this year will be compared to those of the previous two years. All group applicants will share their experiences each others for the purposes of obtaining the best high-strength Ti-based alloys combined with excellent surface-modifications during the 3-year study. The final goal of this research is not only to submit all the individual results to be published in international journals, but also to wholly establish the systematically high-performance database for industrial applications.

Keyword(s)

高強度鈦合金
高溫腐蝕
腐蝕動力學
反應機制
表面改質
high-strength titanium alloys
high-temperature corrosion
corrosion kinetics
reaction mechanisms
surface-modifications

DSpace CRIS

Temperature Effects on the High-Temperature Corrosion Behavior of High-Strength Titanium-Based Alloys

基本資料

Description