(中国科学院 金属研究所,沈阳 110016)
摘 要: 利用激光共聚焦显微镜、扫描电子显微镜以及电子背散射衍射(EBSD)技术观察Ti60合金在高应力水平下的保载疲劳损伤行为。通过激光共聚焦显微镜观察发现,随着循环周次的增加,初生α相内产生的滑移线数量及滑移带宽度均有增加。EBSD分析结果表明,循环1 000周次后,观察到部分α晶粒发生偏转,材料的织构强度增加,织构类型发生变化。由于晶粒软硬取向不同,材料中发生应力重新分配现象,各晶粒之间产生协调作用,硬取向晶粒发生偏转,出现织构增强的特征。SEM观察到保载疲劳断口裂纹源处存在大量准解理小平面。
关键字: Ti60合金;保载疲劳;电子背散射衍射(EBSD);原位观察;显微组织
(Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China)
Abstract:The dwell fatigue damage behavior and deformation mechanism of Ti60 alloy were studied using laser scanning confocal microscope, SEM and EBSD. It is found that, with the increase of cycles, the amount and width of slip band in primary α phase increase. The EBSD results show that, after 1 000 cycles, partial α grains turn angles. The intensity and type of texture are changed. Because of different orientations of grains, the stress redistribution exists in materials. Strong grains turn angles and the textures are strengthened. The SEM observation exhibits that the quasi-cleavage facets form on the fracture surface.
Key words: Ti60 alloy? dwell fatigue; EBSD; in-situ observation; microstructure