(1. 海軍航空工程學(xué)院 青島校區(qū)，青島 266041；
2. 東北大學(xué) 材料與冶金學(xué)院，沈陽 110004)
摘 要: 為研究激光熔覆技術(shù)修復(fù)某定向凝固航空葉片，采用Nd:YAG脈沖激光器在定向凝固DZ22基體表面熔覆兩種自配鎳基合金粉末，研究基體和熔覆層在1 000 ℃高溫環(huán)境中涂覆Na2SO4(質(zhì)量分數(shù)，75%)+NaCl(質(zhì)量分數(shù)，25%)混合鹽飽和水溶液的熱腐蝕行為。結(jié)果表明：基體單位面積質(zhì)量的變化量明顯高于熔覆層腐蝕試樣單位面積質(zhì)量的變化量；在高溫腐蝕開始階段，腐蝕速度較快；達到一定時間后，腐蝕變緩，速率保持恒定；熔覆層的抗高溫腐蝕性能優(yōu)于基體材料的抗高溫腐蝕性能；基體表面氧化物包括Al2O3、Cr2O3、TiO2和WO2等；粉末D熔覆層的抗高溫腐蝕能力優(yōu)于粉末A熔覆層的；氧化層結(jié)構(gòu)復(fù)雜，由氧化物、碳化物和氯化物混合生成；熔覆層表面析出相含有Hf，以碳化物的形式析出；熔覆粉末在熔凝過程中和基體材料之間存在著熔質(zhì)對流，使得熔覆層與基體形成良好的冶金結(jié)合。
關(guān)鍵字: 熱腐蝕；激光熔覆；葉片；定向凝固；顯微組織
（1. Qingdao Branch of NAEI, Qingdao 266041, China;
2. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China）
Abstract:In order to repair a directionally solidified aero blade, laser cladding on DZ22 substrate using two kinds of Ni-based alloy powder by Nd:YAG laser was carried out. The hot corrosion behaviors of the substrate and the cladding layer in Na2SO4(75%, mass fraction)+NaCl(25%, mass fraction) at 1 000 ℃ were investigated. The results show that, the mass variation per unit area of the substrate is obviously higher than that of the cladding layers. The corrosion rate is high at the beginning of the hot corrosion, the rate is low after a certain time, the hot corrosion resistant performance of the cladding layers is better than that of the substrate, the oxides of the substrate includes Al2O3, Cr2O3, TiO2 and WO2. The hot corrosion resistant performance of the cladding layer of the powder D is better than that of the powder A. The products include oxides, carbides and chlorides. Hf is precipitated in the cladding layer with the form of carbides, the convection exists between the cladding powder and the substrate in the fused process. The fine metallurgical bonding is formed between the cladding layer and the substrate.
Key words: hot corrosion; laser cladding; blade; directional solidification; microstructure
