K4169镍基高温合金薄壁机匣的热疲劳行为
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摘要
采用荧光检测、光学显微镜(OM)和扫描电镜(SEM)等手段研究了K4169镍基高温合金薄壁机匣精铸件在航空发动机服役过程中的热疲劳裂纹的扩展规律及断裂方式,探讨了其疲劳断裂的扩展机制。结果表明,K4169合金薄壁机匣的热疲劳残影裂纹主要起源于外表面加工的缺口敏感处的碳化物,为多源开裂;在循环热应力下,主裂纹沿强度较低的晶界或与枝晶生长方向呈45°的方向进行扩展。晶界上碳化物的组成、分布及高温氧化是影响其裂纹扩展的主要因素,其断裂方式为准解理-韧窝混合断裂。
Thermal fatigue behavior of K4169 Ni-based superalloy for thin-walled investment castings in the process of aero-engines service was analyzed by the fluorescent microscopic examination method,optical microscopy(OM)and scanning electron microscope(SEM),and the fatigue crack initiation and propagation mechanism were also described.The results indicate that almost all the primary fatigue cracks are initiated from the carbides at the notch sensitivity of specimen formed during the machining process,Subsequently,only one or two small thermal fatigue cracks can continue to grow and propagate along apreferential direction with the dendrite growth direction or along the intergranular region which carbides can be easy cracked due to different thermal expanding coefficients of the matrix and the carbides,and the crack of MC carbides either at grain boundaries or within the grain interior as well as the high-temperature oxidation are played an important role on crack propagation.The rapid fatigue fracture morphology exhibits quasi-cleavage and dimples feature.
Thermal fatigue behavior of K4169 Ni-based superalloy for thin-walled investment castings in the process of aero-engines service was analyzed by the fluorescent microscopic examination method,optical microscopy(OM)and scanning electron microscope(SEM),and the fatigue crack initiation and propagation mechanism were also described.The results indicate that almost all the primary fatigue cracks are initiated from the carbides at the notch sensitivity of specimen formed during the machining process,Subsequently,only one or two small thermal fatigue cracks can continue to grow and propagate along apreferential direction with the dendrite growth direction or along the intergranular region which carbides can be easy cracked due to different thermal expanding coefficients of the matrix and the carbides,and the crack of MC carbides either at grain boundaries or within the grain interior as well as the high-temperature oxidation are played an important role on crack propagation.The rapid fatigue fracture morphology exhibits quasi-cleavage and dimples feature.
引文
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[14]李友林,袁超,郭建亭.铸造镍基高温合金K445的热疲劳行为[J].金属学报,2006,42(10):1 056-1 060.
[15]郭建亭,袁超,侯介山.高温合金的蠕变及疲劳-蠕变-环境交互作用规律和机理[J].中国有色金属学报,2011,21(3):487-504.
[2]王会阳,安云岐,李承宇,等.铸造高温合金材料的研究进展[J].材料导报,2011,25(S2):482-487.
[3]谢君,于金江,孙晓峰,等.K416B镍基高温合金在700℃的高周疲劳行为[J].金属学报,2016,52(3):257-262.
[4]武丹,田礼熙,马朝利,等.镍基单晶高温合金的拉伸断裂行为[J].材料导报,2016,30(12):76-80.
[5]徐涛,高行山,温志勋,等.镍基单晶高温合金热机械疲劳本构模型研究[J].稀有金属材料与工程,2015,44(1):108-112.
[6]夏鹏成,韩冠朋,谢鲲,等.高温合金热疲劳实验机的研制及实验研究[J].材料导报,2013,27(6):20-22.
[7]谢孝昌,柴志刚,李权,等.直接时效GH4169合金疲劳断口分析研究[J].航空材料学报,2015,35(5):46-56.
[8]康茂东,高海燕,王俊,等.K4169合金铸件的常温疲劳断裂行为[J].上海交通大学学报,2012,46(9):1 461-1 465.
[9]肖旋,许辉,秦学智,等.3种铸造镍基高温合金热疲劳行为研究[J].金属学报,2011,47(9):1 129-1 134.
[10]夏鹏成,于金江,孙晓峰,等.DZ951合金的热疲劳性能[J].稀有金属材料与工程,2008,37(1):50-53.
[11]韩增祥.温度对变形高温合金热疲劳性能的影响[J].燃气涡轮试验与研究,2007,20(11):53-57.
[12]杨健,董建新,张麦仓,等.新型镍基粉末高温合金FGH98的高温疲劳裂纹扩展行为研究[J].金属学报,2013,49(1):71-80.
[13]姚亮亮,张显程,刘峰,等.GH4169镍基高温合金的高温低周疲劳性能[J].机械工程材料,2016,40(4):25-29.
[14]李友林,袁超,郭建亭.铸造镍基高温合金K445的热疲劳行为[J].金属学报,2006,42(10):1 056-1 060.
[15]郭建亭,袁超,侯介山.高温合金的蠕变及疲劳-蠕变-环境交互作用规律和机理[J].中国有色金属学报,2011,21(3):487-504.