(1. 蘭州理工大學(xué) 甘肅省有色金屬新材料省部共建國家重點(diǎn)實(shí)驗(yàn)室, 蘭州 730050;
(2. 蘭州理工大學(xué) 有色金屬合金及加工教育部重點(diǎn)實(shí)驗(yàn)室, 蘭州 730050)
摘 要: 研究新型Co-Al-W合金在800和900 ℃空氣中氧化動力學(xué)及元素Mo、Nb、Ta和Ti對合金高溫氧化行為的影響。結(jié)果表明：在800 ℃氧化100 h后，Co-8.8Al-9.8W(摩爾分?jǐn)?shù), %)和Co-8.8Al-9.8W-2Ta合金的質(zhì)量增加較小，表明其抗高溫氧化能力較強(qiáng)；在900 ℃氧化時(shí)，Co-8.8Al-9.8W-2Mo、Co-8.8Al-9.8W-2Nb、Co-8.8Al-9.8W-2Ta和Co-8.8Al-9.8W-2Ti合金的質(zhì)量增加小于Co-8.8Al-9.8W合金的，表明加入合金元素可以提高合金的抗高溫氧化能力；在不同溫度下，Co-Al-W合金氧化膜表面出現(xiàn)團(tuán)聚、開裂和脫落現(xiàn)象；氧化膜分為3層，外層為Co3O4氧化物，中間層為W、Al和合金元素的復(fù)雜氧化物，內(nèi)層為Co和Al的氧化物。從合金氧化動力學(xué)曲線來看，在800 ℃時(shí)合金元素增強(qiáng)Co-Al-W合金抗高溫氧化能力由強(qiáng)至弱依次為Ta、Ti、Mo、Nb；在900 ℃時(shí)按Ti、Ta、Mo、Nb順序依次減弱。
關(guān)鍵字: Co-Al-W合金；高溫氧化行為；合金元素
Co-Al-W alloys at high temperature
（1. State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials,
Lanzhou University of Technology, Lanzhou 730050, China;
2. Key Laboratory of Non-ferrous Metal Alloys, Ministry of Education,
Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:The oxidization kinetics of novel Co-Al-W supperalloys in air at 800 and 900 ℃, and the effects of alloying elements (Mo, Nb, Ta, Ti) on oxidation behavior of Co-Al-W alloys at high- temperatures were investigated. The results show that after being oxidized at 800 ℃ for 100 h, the mass gain of Co-8.8Al-9.8W or Co-8.8Al-9.8W-2Ta is less, indicating that they have better anti-oxidative ability than other alloys at 800℃. After being oxidized at 900 ℃, the mass gain of Co-8.8Al-9.8W-2Mo, Co-8.8Al-9.8W-2Nb, Co-8.8Al-9.8W-2Ta or Co-8.8Al-9.8W-2Ti is less than that of Co-8.8Al-9.8W alloy, indicating that for anti-oxidant property, Co-8.8Al-9.8W-2Mo, Co-8.8Al-9.8W-2Nb, Co-8.8Al-9.8W-2Ta and Co-8.8Al-9.8W-2Ti alloys are superior to Co-8.8Al-9.8W alloy. There are agglomeration, voids at local scale/alloy interface, crack and deterioration in the oxidation films on Co-Al-W alloy surfaces at different temperatures. The oxide scales exhibit multi-layered structure including an outer layer of Co3O4 oxide, an intermediate mixed layer of oxides of W, Al and alloying elements and an internal attacked layer of oxides of Co and Al. According to the fitted oxidization kinetic curves, the ability of alloying elements (Mo, Nb, Ta, Ti) on the anti-oxidation of Co-Al-W alloy is in an decreasing order of Ta, Ti, Mo, Nb at 800 ℃，but Ti, Ta, Mo, Nb at 900 ℃.
Key words: Co-Al-W superalloy; high-temperature oxidation behavior; alloying element
