Micromechanisms of crack initiation of a Ti-8Al-1Mo-1V alloy in the very high cycle fatigue regime. (September 2021)

• Record Type: Journal Article
• Authors: Gao, Tao; Xue, Hongqian; Sun, Zhidan; Retraint, Delphine; He, Yanli
• Is Part Of: International journal of fatigue. Volume 150(2021)
• Publication Date: 2021-09
• Subjects: Titanium alloy -- Very high cycle fatigue -- Crack initiation micromechanisms -- Slip -- Facets; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2021.106314
• Languages: English
• ISSNs: 0142-1123

Abstract

Highlights: Very high cycle fatigue properties of a Ti-8Al-1Mo-1V alloy were investigated. Micromechanisms of crack initiation were studied by microscopic observations. Intensive plastic slips induced by VHCF were observed in specimen interior. Crack-initiation occurs with the formation of nano-marking facets and flat facets. Large scatter in fatigue life is caused by slip inhomogeneity in different grains. Abstract: Fatigue behavior and damage mechanisms of a Ti-8Al-1Mo-1V alloy were investigated in the very high cycle fatigue (VHCF) regime. Fracture surfaces and slip morphologies of failed specimens were observed to reveal the crack-initiation micromechanisms. The crack initiation area is characterized by nano-marking facets and flat facets surrounded by tearing topography surface (TTS). The VHCF crack initiation is attributed to the formation of nano-marking facets and flat facets in αp grains induced by dislocations and slip activity. The slip activity is the main micro-deformation mechanism while a large scatter in fatigue life can be attributed to slip inhomogeneity.