热暴露对近片层γ-TiAl合金在交变载荷下表面损伤容限的影响研究  

Research on Influence of Thermal Exposure on Surface Damage Tolerance Limitation of Near Lamellar γ-TiAl Alloy Under Alternating Load

作　　者：李艳明 黄泽文[1] 

机构地区：[1]西南交通大学材料先进技术教育部重点实验室,四川成都610031

出　　处：《热加工工艺》2017年第18期62-66,共5页Hot Working Technology

基　　金：国家自然科学基金项目(51271154)

摘　　要：研究了高强度的近片层γ-Ti Al合金Ti-44Al-4Nb-4Zr-0.2Si-1B长期热暴露(700℃,10000 h)前后的显微组织变化,并研究了表面缺陷对高周疲劳性能的影响。对长裂纹的疲劳起裂门槛值,引起疲劳失效的非安全尺寸的短裂纹范围进行分析,确定了该合金在热暴露下的表面缺陷的容忍限度。结果表明:热暴露能提升该合金光滑样品的疲劳强度,增加其对表面缺陷的敏感度。The changes of the microstructure of high strength near lamellar γ-TiAl alloy Ti-44Al-4Nb-4Zr-0.2Si-1B before and after thermal exposure （at 700 ℃ for 10000 h ） were investigated, and the influences of surface defects on the high cycle fatigue behaviour were studied. The fatigue crack threshold value of long cracks and the short crack range with unsafe size which could casue fatigue failure, were analyzed, and then the tolerance limitation of the surface defects of the alloy under thermal exposure was determined. The results show that the fatigue strength of the alloy smooth sample improves after thermal exposure, which can increase its sensitive to surface defects.

关 键 词：Γ-TIAL合金 热暴露 短裂纹 Kitagawa-Takahashi 疲劳 

分 类 号：TG146.23[一般工业技术—材料科学与工程]