时效温度对TB18钛合金显微组织及高周疲劳行为的影响  

Effect of aging temperature on microstructure and high-cycle fatigue behavior of TB18 titanium alloy

作　　者：李波[1] 秦锋英[1] 林苑 张开铭 袁武华[2] LI Bo;QIN Feng-ying;LIN Yuan;ZHANG Kai-ming;YUAN Wu-hua(AVIC The First Aircraft Institute,Xi’an 710089,China;School of Materials Science and Engineering,Hunan University,Changsha 410082,China)

机构地区：[1]中航工业第一飞机设计研究院,陕西西安710089 [2]湖南大学材料科学与工程学院,湖南长沙410082

出　　处：《材料热处理学报》2025年第2期122-129,共8页Transactions of Materials and Heat Treatment

摘　　要：采用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)和疲劳试验机等研究了不同温度时效处理后TB18钛合金的显微组织和高周疲劳行为。结果表明:随着时效温度的升高,TB18钛合金中片层α相的析出逐渐增多,500、525和550℃时效后显微组织的特征分别为集束结构、集束+网篮结构和网篮结构;当时效温度为525℃时,TB18钛合金屈服强度为1231 MPa、抗拉强度为1303 MPa、伸长率为5.8%、高周疲劳寿命为26530周次,具有较佳的综合性能;在高周疲劳状态下,断裂方式为韧性断裂,主裂纹表现为沿晶和穿晶相结合的裂纹扩展模式;此外,微裂纹的萌生机制主要表现为片层α相内产生的位错堆积形成微裂纹、α/β相界面产生的大量滑移线和位错堆积形成微裂纹两种。Microstructure and high-cycle fatigue behavior of TB18 titanium alloy after aging at different temperatures were studied using optical microscope(OM),scanning electron microscopy(SEM),transmission electron microscopy(TEM) and fatigue testing machine.The results show that with the increase of aging temperature,the precipitation of lamellar α phase in the TB18 titanium alloy gradually increases.The characteristics of the microstructure after aging at 500 ℃,525 ℃,and 550 ℃ are clustered structure,clustered+basket structure,and basket structure,respectively.When the aging temperature is 525 ℃,the yield strength of the TB18 titanium alloy is 1231 MPa,the tensile strength is 1303 MPa,the elongation is 5.8%,and the high-cycle fatigue life is 26530 cycles,showing excellent comprehensive performance.In the high-cycle fatigue state,the fracture mode is ductile fracture,and the main crack exhibits a crack propagation mode combining intergranular and transgranular modes.In addition,the initiation mechanism of microcracks mainly manifests as two types:the formation of microcracks by dislocation accumulation in the lamellar α-phase,and the formation of microcracks by a large number of slip lines and dislocation accumulation at the α/β phase interface.

关 键 词：TB18钛合金 微观组织 高周疲劳 断口形貌 微裂纹 

分 类 号：TG146.2[一般工业技术—材料科学与工程]