(1. 蘭州理工大學(xué)省部共建有色金屬先進(jìn)加工與再利用國家重點(diǎn)實(shí)驗(yàn)室，蘭州 730050；
2. 蘭州理工大學(xué)材料科學(xué)與工程學(xué)院，蘭州 730050)
摘 要: Co-Al-W合金是一種由γ′-Co 3(Al,W)相沉淀強(qiáng)化的新型鈷基高溫合金，為了研究微合金化元素鉭對Co-8.8Al-9.8W(摩爾分?jǐn)?shù)，%)合金強(qiáng)化相和高溫氧化行為的影響，運(yùn)用d電子合金設(shè)計(jì)理論和XRD分析方法研究Co-8.8Al-9.8W-xTa (x=0、0.5、1、1.5、2)合金的相組成、γ′強(qiáng)化相的數(shù)量及μ相的析出行為；運(yùn)用SEM和EDAX等方法研究合金高溫氧化膜的組成、顯微組織結(jié)構(gòu)和元素分布，并計(jì)算合金的氧化激活能。結(jié)果表明：鉭元素含量增加，合金中γ′強(qiáng)化相的數(shù)量增多，對μ相析出的抑制程度增加。Co-8.8Al-9.8W-xTa合金的氧化膜主要由3層組成，最外層主要為鈷的氧化物，中間過渡層為鎢、鋁和鉭的復(fù)雜氧化物，最內(nèi)層主要為鋁的氧化物。鉭元素提高合金氧化膜最內(nèi)層中鋁氧化物的致密性和穩(wěn)定性。1.5Ta合金的氧化膜具有最佳的致密度和穩(wěn)定性，氧化激活能最高，抗氧化能力最強(qiáng)。
關(guān)鍵字: Co-Al-W合金；高溫氧化；激活能；氧化膜；鉭
（1. State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metal,
Lanzhou University of Technology, Lanzhou 730050, China;
2. School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:With the precipitation strengthening phase of ternary compound γ′-Co3(Al,W), Co-Al-W superalloy is a novel cobalt-based superalloy. In order to study the effects of alloying element tantalum on the strengthening phase and high temperature oxidation behavior of Co-8.8Al-9.8W superalloy, the phase composition, the amount of strengthening phase and precipitation behavior of μ phase of Co-8.8Al-9.8W superalloy with different tantalum contents were investigated with d electrons alloy design theory and XRD analysis. Then the composition, microstructure and element distribution of the high temperature oxide films of Co-8.8Al-9.8W superalloy with different tantalum contents were studied by SEM and EDAX methods. And the activation energy of Co-8.8Al-9.8W superalloy with different tantalum content was calculated. The results show that with tantalum content increasing, the number of γ′ strengthening phase of the Co-Al-W superalloy increases and the μ phase separation is inhibited. The oxide film of Co-8.8Al-9.8W-xTa (x=0, 0.5, 1, 1.5, 2) superalloy mainly consists of three layers, the outermost layer mainly is cobalt oxide, the intermediate layer is tungsten, aluminum and tantalum complex oxides, and the inner layer is made up of aluminum oxide. Tantalum element improves the density and stability of oxide film of aluminum oxide. The oxide film of 1.5Ta superalloy has the best compactness and stability, and the 1.5Ta superalloy has the highest oxidation activation energy and the strongest antioxidant capacity.
Key words: Co-Al-W superalloy; high-temperature oxidation; activation energy; oxide film; tantalum
