(北京航空材料研究院， 北京 100095)
摘 要: 單晶鎳基高溫合金已廣泛用于制造先進(jìn)燃?xì)鉁u輪葉片， 但這種合金至今仍被忽視的薄弱環(huán)節(jié)是它的中溫Ⅰ階蠕變伸長量遠(yuǎn)高于高溫蠕變，而且與高溫蠕變相比， 中溫Ⅰ階蠕變對取向偏離、 合金成分和熱處理組織的變化更為敏感。 雖然預(yù)蠕變引進(jìn)較高的位錯密度能有效抑制中溫蠕變， 但在實用上仍有困難。 在選用單晶合金作為渦輪葉片時，應(yīng)考慮到先進(jìn)的二代和三代單晶在中溫下的抗變形能力不如一代單晶， 同時中溫大應(yīng)力狀態(tài)下的葉片根部可能過度伸長。
關(guān)鍵字: 單晶高溫合金； 中溫蠕變； 合金化； 顯微組織； 應(yīng)變； 渦輪葉片
—An important factor of
turbine blade extension
（Beijing Institute of Aeronautical Materials, Beijing 10095, China）
Abstract: The single crystal Ni-base superalloys were widely used for manufacturing advance gas turbine blades, but the ignored weakness of these alloys to date is that the extent of primary creep at intermediate temperature is much higher than that at high temperature. Moreover, compared with high temperature creep, the primary creep strain at intermediate temperature is extraordinary sensitive to changes in the orientated deviation, composition and the heat-treated microstructure. Although the high-density dislocations introduced by pre-creep treatment can restrict the intermediate temperature creep, it is difficult for application in practice. As single crystal alloys are selected as manufacturing turbine blades, it is considered that the resistance to deformation of the second or the third generation single crystal superalloys at intermediate temperature is inferior to first generation alloys and the excessive extension of blade root could take place at the service environment of intermediate temperature and high stress.
Key words: single crystal superalloys; intermediate temperature creep; alloying; microstructure; strain; turbine blades
