性能的影響
( 1. 沈陽大學(xué) 機械工程學(xué)院， 沈陽 110044；
2. 東北大學(xué) 材料與冶金學(xué)院，沈陽 110004；
3. 中國科學(xué)院 金屬研究所，沈陽 110016)
摘 要: 研究了高溫精煉處理對鑄造鎳基高溫合金組織與性能的影響。普通鑄造鎳基合金枝晶組織粗大， 晶界碳化物呈鏈狀分布， 晶內(nèi)碳化物呈草體漢字狀密集分布于枝晶間， 是合金塑性低的主要原因。 經(jīng)高溫精煉處理后， 合金的枝晶組織細(xì)化，晶界及枝晶間的碳化物數(shù)量減少， γ+γ′共晶相數(shù)量增加， 晶界碳化物呈不連續(xù)質(zhì)點狀分布， 晶內(nèi)碳化物的密集程度下降， 拉伸塑性和蠕變（持久）壽命得以明顯提高。經(jīng)1650℃， 5min高溫熔體處理后， 合金室溫延伸率由3.5%提高到9.2%， 700℃高溫塑性由2.0%提高到8.0%， 900℃高溫塑性由2.8%提高到9.6%， 蠕變壽命由34h提高到52h， 蠕變塑性由4.3%提高到6.11%。 推薦的最佳高溫精煉處理制度為1650℃保溫4h。 分析了高溫精煉處理對合金液態(tài)結(jié)構(gòu)、 凝固組織與性能的影響機理。
關(guān)鍵字: 高溫精煉處理； 鑄造鎳基高溫合金； 組織; 力學(xué)性能
CAI Qing-kui1, 2, HU Zhuang-qi3
（ 1. School of Mechanical Engineering, Shenyang University, Shenyang 110044, China;
2. School of Materials and Metallurgy,
Northeastern University, Shenyang 110004, China;
3. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract: The effects of the melt superheating treatment on the microstructure and mechanical properties of a cast nickel-base superalloy were investigated. A large amount of coarse or needle-like carbides within the grain interior or at grain boundary in this alloy as conventional cast, is very harmful to the mechanical properties. It is suggested that the melt superheating treatment at high temperature can be conducive to the improvement of the ductility of the alloy. The results show that the microstructure of the alloy can be significantly influenced by the melt superheating treatment, that is, the dendritic structure is refined, and the amount of carbides is reduced. Consequently, after treated at 1650℃ for 5min, tensile ductility of cast alloy is increased remarkably from 3.5% to 9.2% at room temperature, from 2.0% to 8.0% at 700℃ and from 2.4% to 9.6% at 900℃, respectively, without loss of its high strength. Meanwhile, the creep life of superalloy lower than 225MPa at 975℃ is also improved obviously.
Key words: melt superheating treatment; cast nickel-base superalloy; microstructure; mechanical property
