(1. 沈陽工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，沈陽 110023；
2. 沈陽化工學(xué)院 機(jī)械工程學(xué)院，沈陽 110142)
摘 要: 通過蠕變性能測(cè)試及組織形貌觀察，研究不同形態(tài)孔洞缺陷對(duì)單晶鎳基合金蠕變性能的影響，針對(duì)合金中存在有/無裂紋孔洞等鑄造缺陷，對(duì)高溫蠕變期間近有/無孔洞區(qū)域的應(yīng)力分布進(jìn)行有限元分析，根據(jù)拉應(yīng)力載荷下近孔洞區(qū)域的微觀應(yīng)力分布特性，分析不同形態(tài)孔洞區(qū)域應(yīng)力分布對(duì)單晶合金蠕變行為及組織演化的影響。結(jié)果表明：在高溫蠕變期間，近有/無裂紋孔洞區(qū)域的應(yīng)力分布對(duì)合金中γ¢相筏形化的形態(tài)有明顯影響，在有/無裂紋孔洞兩側(cè)極點(diǎn)處，存在最大應(yīng)力值，且可致使其裂紋沿垂直于應(yīng)力軸方向發(fā)生萌生與擴(kuò)展；與無裂紋孔洞相比，在有裂紋孔洞兩側(cè)的極點(diǎn)處應(yīng)力值較大，隨著蠕變的進(jìn)行，在較大應(yīng)力處易于發(fā)生裂紋的擴(kuò)展是合金具有較低蠕變壽命的主要原因。
關(guān)鍵字: 單晶；鎳基合金；孔洞形態(tài)；有限元分析；應(yīng)力分布；蠕變壽命
single crystal nickel-base superalloy
（1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110023, China;
2. School of Mechanical Engineering, Shenyang Institute of Chemical Technology, Shenyang 110142, China）
Abstract:By means of creep properties measurement and microstructure observation, the influence of cavity morphology on the creep behaviors of a single crystal nickel-base alloy was investigated. Due to the cavity with or without cracks exists in the as-cast superalloy, the stress distribution near the cavity with or without cracks during high temperature creep was analyzed by finite elements analysis method (FEM), and the influence of the stress distribution near the cavity regions on the creep behaviors and microstructure evolution of the superalloy was discussed according to the feature of the stress distribution near the cavity. The results show that, during high temperature creep, the stress distribution near the cavity with or without cracks has an obvious effect on the morphology of the rafted γ¢ phase in the superalloy, the maximum stress value which appears in two sides of the cavity with or without cracks may promote the initiation and propagation of the cracks along the direction vertical to the applied stress axis. Compared with the crack-free cavity, the bigger stress value appears in two sides of the cavity with cracks which propagates easily as creep goes on, this is the main reason resulting in the alloy with shorter creep lifetime.
Key words: single crystal; nickel-based superalloys; cavity morphology; FEM analysis; stress distribution; creep lifetime
