择优取向层片组织TiAl合金的室温疲劳行为  

Room-temperature fatigue behavior of TiAl alloy with preferentially oriented lamellar microstructure

作　　者：万文娟[1] 韩波[1] 韩伟[2] 张继[1] WAN Wen-juan HAN Bo HAN Wei ZHANG Ji(Beijing Key Laboratory of Advanced High Temperature Materials, Central Iron and Steel Research Institute, Beijing 100081, China Functional Material Research Institute, Central Iron and Steel Research Institute, Beijing 100081, China)

机构地区：[1]钢铁研究总院高温合金新材料北京市重点实验室,北京100081 [2]钢铁研究总院功能材料研究所,北京100081

出　　处：《钢铁研究学报》2017年第1期67-74,86,共9页Journal of Iron and Steel Research

摘　　要：采用旋转弯曲加载方式,评价了择优取向层片组织Ti-47.5Al-2.5V-1.0Cr-0.2Zr(原子数分数,%)合金的室温高周疲劳性能,并采用扫描电镜对疲劳断口进行了观察和分析。结果显示,实验合金的应力-寿命(S-N)曲线呈现平直形态,符合Basquin方程;其条件疲劳极限为477MPa,相当于其抗拉强度的83%。断口观察发现,疲劳试样以穿层片解理方式发生断裂。疲劳裂纹主要沿位于试样表面层、与外加应力成30°~90°的层片界面萌生,之后以穿层片方式发生扩展。在同一应力水平下,疲劳寿命随疲劳源尺寸增加而减少,疲劳源尺寸波动是导致疲劳寿命大幅分散的主要原因。The room-temperature high-cycle fatigue performance of Ti-47.5A1-2.5V-1.0Cr-0.2Zr （at. ~//0） alloy with a preferentially oriented lamellar microstructure has been evaluated by loa＆controlled rotating bending fatigue tests, and the fracture surfaces have also been observed and analyzed by scanning electron microscopy. The results show that the studied alloy exhibits a flat S-N curve which follows the Basquin equation. The fatigue limit is 477 MPa, which equals to 83% of the ultimate tensile strength. The fracture surface observation proves that the fail- ure of these specimens is caused by a translamellar cleavage mode. Fatigue cracks mostly initiate along lamellar in- terfaces which located at specimensr surface and also have an angle of 30°- 90° with the applied stress, and then propagate in a translamellar way. Moreover, at the same stress level, fatigue life decreases with increasing the size of crack initiator, and the large fatigue-life scatter of the studied alloy mainly results from the variability of crack- initiator size.

关 键 词：TIAL 择优取向层片组织 S-N曲线 疲劳 疲劳寿命 

分 类 号：TG146.23[一般工业技术—材料科学与工程]