长期时效对GH4169合金组织演化及低周疲劳行为的影响  

INFLUENCES OF LONG-TERM AGING ON MICROSTRUCTURE EVOLUTION AND LOW CYCLE FATIGUE BEHAVIOR OF GH4169 ALLOY

作　　者：安金岚 王磊[1] 刘杨[1] 胥国华[2] 赵光普[2] 

机构地区：[1]东北大学材料各向异性与织构教育部重点实验室,沈阳110819 [2]钢铁研究总院高温材料研究所,北京100081

出　　处：《金属学报》2015年第7期835-843,共9页Acta Metallurgica Sinica

基　　金：国家高技术研究发展计划项目2012AA03A513;教育部资助技术项目625010337资助~~

摘　　要：研究了GH4169合金在750℃长期时效中的组织演化及其对低周疲劳行为的影响规律.结果表明,随时效时间的延长,合金中y″相尺寸逐渐增大、体积分数减少;δ相尺寸增大、体积分数增加;长期时效后合金低周疲劳最大循环应力响应降低,疲劳寿命缩短.随循环周次的增加,合金循环应力响应均依次呈循环硬化、稳定、而后软化的特征.合金时效过程中y″相尺寸增大和体积分数降低,导致其对合金的强化效果减弱,由此循环应变的应力响应降低;而时效中长针状d相及其周围的无析出带的生成成为裂纹扩展路径,导致疲劳寿命下降.GH4169 superalloy is one kind of important metallic materials used for manufacturing turbine discs in aero-engine. In order to meet the demand of higher strength, high ratio alloying elements have to be added, resulting in the complex microstructure evolution during the long- term service at elevated temperature. Furthermore, the turbine disc usually bears overloading which will lead to the low cycle fatigue（LCF） damage in real working and result in fatal security problem. Besides, it is meaningful to decide the relationship between the microstructure evolution and performance degradation. In the present work, microstructure evolution and LCF behavior of GH4169 alloy during long- term aging were investigated. The microstructure evolutions of GH4169 alloy during long-term aging at 750 ℃ for 500, 1000, 1500 and 2000 h and the influences of long-term aging on the LCF behavior were investigated. The results show that the size of γ ″ phases increases and the volume fraction decreases with the increase of aging time, compared with the increase of both size and volume fraction of δ phases. Both the fatigue strength and fatigue life of the alloy decrease with the increase of aging time. For the specimen aged for the same time, the cyclic stress firstly contributes to cyclic hardening, then cyclic stability, and finally cyclic softening with the increase of cyclic numbers. It is found that the decrease of cyclic stress contribution is slightly effected by the size of γ″ phases increase and volume fraction decrease after long-term aging. Therefore, the LCF life of the alloy decreases since the crack easily propagates along with the long needle-like d phases and the γ″ phases precipitate free zones.

关 键 词：GH4169合金 长期时效 组织演化 低周疲劳 

分 类 号：TG132.3[一般工业技术—材料科学与工程]