Dwell fatigue property and fracture behaviour of Ti60 titanium alloy at room temperature

• Main Authors: LIU Shi-shuang, QIU Ping, CAI Jian-ming, LI Juan, HUANG Xu, YU Hui, LIU Li-gang
• Format: Article
• Language: zho
• Published: Journal of Materials Engineering 2019-07-01
• Series: Journal of Materials Engineering
• Subjects: Ti60 titanium alloy; dwell fatigue; dwell fatigue sensitivity; plastic strain accumulation; quasi-cleavage facet
• Online Access: http://jme.biam.ac.cn/CN/Y2019/V47/I7/112
• ISSN: 1001-4381; 1001-4381

The low cycle fatigue (LCF) property and low cycle dwell fatigue (LCDF) property of bimodal structure and lamellar structure for Ti60 titanium alloy under high peak stress were studied by means of optical microscope (OM), scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). The results show that microstructure has little effect on LCF property, while significantly influences LCDF property. The dwell fatigue sensitivity of bimodal structure is higher than that of lamellar structure. Under dwell loading condition, the fatigue life decreases remarkably. The fatigue life decreases with the increase of the peak stress, while the dwell fatigue sensitivity increases. Within the same cycle, plastic strain accumulation of LCDF is greater than that of LCF, and the plastic strain accumulation of bimodal structure is more than that of lamellar structure. The LCF crack initiates at the specimen surface with single source, while LCDF crack originates inside of specimen with multiple sources. There are quasi-cleavage facets on the fracture surface. The density of facets for bimodal structure is higher than that of lamellar structure.