鈦-５鋁-１錫-１鉻-１鐵合金相變化

Phase Transformations of the Ti- 5Al-1Sn -1Cr - 1Fe Alloy

簡正源

指導教授 ： 趙志燁

國立屏東科技大學/工學院/機械工程系所/碩士(2009年)

https://doi.org/10.6346/NPUST.2009.00189

摘要

鈦-5鋁-1錫-1鉻-1鐵合金經適當的連續熱軋延後，其機械性質範圍，抗拉強度介於980~1060MPa、降伏強度介於860~1000MPa、延伸率則可達24~40%範圍。本文主要目的在探討熱處理對鈦-5鋁-1錫-1鉻-1鐵合金之顯微結構的影響，研究結果顯示：合金在1030℃/1小時固溶處理後，其顯微結構為雙晶型過飽和的麻田散鐵組織。合金900℃加熱1小時，其顯微結構具(α+β)雙相組織，其中冷卻後α相區可觀察到具有差排的針狀組織。合金800℃加熱1小時，其顯微結構具(α+β)雙相組織，其中冷卻後α相區觀察到界面差排現象，並具有超晶格之六方最密堆積(HCP)結構的點。合金經480-540℃/1-8小時，不同時效處理後，在α相區域基地中，可觀察到ω相析出。此外，研究顯示：本合金α/β轉換溫度約在965-980℃，麻田散鐵轉換溫度(Ms)約在815-830℃。

關鍵字

鈦合金 ； 相變化 ； 麻田散鐵 ； 超晶格 ； ω相

並列摘要

During the continuous hot-rolling, the ultimate tensile strength, yielding strength and elongation of the Ti-5Al-1Sn-1Cr-1Fe alloy are in the range of 980~1060MPa, 860~1000MPa and 24-40%, respectively. The main purposes of the present studies are to investigate the effects of heat treatment on the microstructures of the alloy. Some results are described as following. Being heated on 1030℃ for 1 hour, the microstructure of the present alloy is lamellar twin martensite. When heated on 900℃ for 1 hour, the micro- structure of the present alloy is a mixture (α+β) duplex phases. In addition, a martensite transformation would occur within the β-phases region resulting in forming a martensite with high density dislocation during the quenching. Being heated at 800℃, the microstructure of the alloy is a mixture (α+β) phase. In the meanwhile, some precipitates with an hcp superlattice structure were found within the α-phase region. During the aging processing, 480-540℃ for 1-8 hours, some ω-phase precipitates formed within the matrix. Moreover, base on the examination of scanning electron micrograph, the α/β transition temperature of the present alloy will be in the range between 965℃ and 980℃, and the temperature of the martensite transition (Ms) being in the range between 815℃ and 830℃.

並列關鍵字

Ti-alloy ； microstructure ； martensite ； superlattice ； ω-phase

參考文獻

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