(1. 沈陽工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，沈陽 110870；2. 沈陽黎明航空發(fā)動(dòng)機(jī)股份有限公司，沈陽 110043)
摘 要: 通過測定一種鎳基單晶合金的蠕變曲線和觀察微觀組織及對(duì)合金斷裂后位錯(cuò)組態(tài)進(jìn)行分析，研究中溫高應(yīng)力條件下鎳基單晶合金的組織演化及斷裂特征。結(jié)果表明：在760 ℃、700 MPa條件下，合金蠕變斷裂后的斷口表面由類臺(tái)階狀形貌組成，且臺(tái)階取向相同，臺(tái)階的兩個(gè)棱邊與á110ñ晶向平行，臺(tái)階的上平面平行于{001}晶面。合金凝固形成的共晶區(qū)是合金薄弱區(qū)域，裂紋在該區(qū)域萌生和擴(kuò)展，并最終導(dǎo)致合金的蠕變斷裂。800 ℃、750 MPa蠕變期間，合金中的g ¢相可形成與應(yīng)力軸垂直的類N−型筏狀結(jié)構(gòu)，但筏狀g ¢相的尺寸較短，在合金的g基體通道及g ¢/g兩相界面處存在大量位錯(cuò)網(wǎng)，有部分á110ñ超位錯(cuò)切入筏狀g ¢相內(nèi)。(1/2) 位錯(cuò)由g ¢/g相界面切入 g ¢相后發(fā)生位錯(cuò)分解，可形成(1/3)á112ñ超肖克萊不全位錯(cuò)+層錯(cuò)的位錯(cuò)組態(tài)，當(dāng)有單個(gè)位錯(cuò)穿過層錯(cuò)區(qū)時(shí)，致使位錯(cuò)與層錯(cuò)襯度相互重疊，使層錯(cuò)條紋明暗襯度發(fā)生變化。
關(guān)鍵字: 單晶鎳基高溫合金；斷口表面；蠕變；組織演化；位錯(cuò)
（1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China;
2. Shenyang Liming Aero-engine Corporation, Shenyang 110043, China）
Abstract:By measuring the creep curves, observing the microstructure and analyzing dislocation configuration of the nickel-base single crystal superalloy after being fractured at medium temperature and high stress, the rupture fracture surface characters and deformation mechanism of the nickel-base single crystal superalloy were studied. The results show that, the rupture fracture surface is made of lots of steps plane, which posses the same orientation and two edges with á110ñ orientation for each step, and the upper plane of step parallel to the {001} plane faces after creep up to fracture at 760 ℃ and 760 MPa. The formed eutectic area during lasting solidification is the weak area where the crack initiation and propagation happen during creep, eventually lead to alloy creep rupture. The formed N-shape like ordered g ¢ phase structure vertical to the stress axis during creep at 800 ℃ and 750 MPa, but the raft length of ordered g ¢ phase is shorter. There are lots of dislocation nets in matrix channel and ordered g ¢/g two-phase interface place, and a part of á110ñ super dislocations shear the ordered g ¢ phase raft. The dislocation is decomposition into partial dislocation (1/3)á112ñ + stacking fault configuration when the (1/2) dislocation shears the g ¢ phase through g ¢/g phase interface. When a single dislocation slips through the stacking fault area, the dislocation and stacking fault overlap, and the dislocations lining stripe light and shade changes.
Key words: single crystal nickel-base superalloy; fracture surface; creep; microstructure evolution; dislocation
