Study on crack growth and fatigue life in TC6 titanium alloy by integrated phase proportion and grain size modeling. (1st October 2020)

• Record Type: Journal Article
• Authors: Zhang, Jie; Wu, Hejun; Wang, Yuting; Zhou, Jianqiu
• Is Part Of: Engineering fracture mechanics. Volume 237(2020)
• Publication Date: 2020-10-01
• Subjects: Dual-phase -- Phase proportion -- Grain size -- Crack growth -- Fatigue life; Fracture mechanics -- Periodicals; Rupture, Mécanique de la -- Périodiques; Fracture mechanics; Periodicals; 620.112605
• DOI: 10.1016/j.engfracmech.2020.107235
• Languages: English
• ISSNs: 0013-7944

Abstract

Highlights: The content and arrangement of different grains may affect the way of dislocations penetrate grain boundaries. The more β-Ti content and smaller grain size, the slower the crack growth rate. The change of phase content will ultimately affect fatigue life. Abstract: In this paper, a theoretical model is developed to reveal the crack growth and fatigue life in polycrystalline alloys with dual-phase microstructure. The present quantitative analysis proves that the grain size and phase proportion can efficaciously affect the crack growth and fatigue life. The dislocations emitted from the crack tip and penetrated three types of grain boundaries (GBs) under cyclic shear stress. According the different boundaries, we obtained the calculation of three kinds of critical penetration stress ( τcr ) and dislocation stress ( τ1 ). Moreover, it can be worked out the crack growth and fatigue life. As the results suggest that the fatigue crack growth reduces with decreases of grain size and increases of minor phases proportion ( Xβ ). Comparison of fatigue life prediction, we derived the fatigue fracture characteristics. In a word, the results offer awareness to improve the mechanical properties in dual-phase titanium alloy by optimizing the microstructures.