【摘要】：本文通過設(shè)計和制備出有/無Ru鎳基單晶合金,對合金進行不同工藝熱處理、蠕變性能測試和組織形貌觀察,研究了元素Ru和熱處理工藝對鎳基單晶合金組織與蠕變性能的影響,并采用熱力學(xué)方法進行不同溫度的層錯能計算,討論了溫度對合金層錯能及變形機制的影響。結(jié)果表明,無Ru鎳基單晶合金在蠕變期間析出大量針狀TCP相,是具有較低蠕變性能的主要原因,加入元素Ru可抑制合金中析出TCP相,并大幅度提高鎳基單晶合金的蠕變壽命。4%Ru鎳基單晶合金經(jīng)1050℃?3h A.C時效及完全處理可使合金獲得較好的組織與蠕變性能,其中,測定出合金在760℃/780MPa、980℃/200MPa和1100℃/120MPa的蠕變壽命分別為423h、333h和232h。在低于850℃蠕變期間,合金中??相仍保持立方形態(tài),其變形機制是位錯在?基體相中滑移和剪切進入??相,且剪切進入??相的位錯可發(fā)生分解,形成不全位錯加層錯的位錯組態(tài)。在高于980℃蠕變期間,合金中??相已沿垂直于應(yīng)力軸方向轉(zhuǎn)變成筏狀結(jié)構(gòu),穩(wěn)態(tài)蠕變期間的變形機制是位錯在基體中滑移和攀移越過筏狀??相,蠕變后期的變形機制是位錯在基體中滑移和剪切進入筏狀??相,且剪切進入筏狀??相的位錯不發(fā)生分解。溫度對合金層錯能的影響是致使合金在不同溫度有不同變形機制的主要原因。合金在低于850℃時有較低的層錯能,剪切進入??相的位錯可發(fā)生分解,形成不全位錯加層錯的位錯組態(tài);隨蠕變溫度提高,合金的層錯能增大,是致使合金在高溫蠕變期間剪切進入??相的位錯不發(fā)生分解的主要原因。蠕變后期,合金中主/次滑移系中位錯的交替開動,可使??相發(fā)生粗化和扭曲,并在垂直于應(yīng)力軸的??/?兩相界面發(fā)生裂紋的萌生和擴展,直至發(fā)生斷裂,是鎳基單晶合金在高溫蠕變期間的損傷和斷裂機制。
[Abstract]:In this paper, a single crystal alloy with or without Ru was designed and prepared. The alloy was subjected to different heat treatment, creep property test and microstructure observation. The effect of element Ru and heat treatment on microstructure and creep properties of Ni-base single crystal alloy was studied. The stacking fault energy at different temperatures was calculated by thermodynamic method. The effect of temperature on stacking fault energy and deformation mechanism was discussed. The results show that a large number of needle-like TCP phases are precipitated during creep, which is the main reason for the low creep properties of Nickel-base alloy without Ru. The addition of the element Ru can inhibit the precipitation of TCP phase in the alloy. The creep life of nickel base single crystal alloy was greatly improved. The microstructure and creep properties of 4%Ru nickel base single crystal alloy were obtained by aging and complete treatment at 1050 鈩，

本文編號：2341339