Investigation on fatigue crack growth behavior for commercial pure titanium at different crack tip plastic deformed levels. (April 2019)

• Record Type: Journal Article
• Authors: Li, Jian; Su, Chuan-Yi; Lu, Lei; Zhang, Peng; Chang, Le; Miao, Xin-Ting; Zhou, Bin-Bin; He, Xiao-Hua; Zhou, Chang-Yu
• Is Part Of: Theoretical and applied fracture mechanics. Volume 100(2019)
• Page Start: 1
• Page End: 13
• Publication Date: 2019-04
• Subjects: Fatigue crack growth -- Commercial pure titanium -- Load ratio -- Load amplitude -- Fracture morphologies; Fracture mechanics -- Periodicals; 620.1126
• DOI: 10.1016/j.tafmec.2018.12.010
• Languages: English
• ISSNs: 0167-8442

Abstract

Graphical abstract: Highlights: More plastic strain energy will be consumed in the high load amplitude. Δ J ac and Δ J ′ are suitable to describe phenomena in the fracture surface. The crack growth resistance is higher under high load ratio. The fracture morphologies are all dimples at the late stage of crack growth. The data obey the Paris' law mode in the rapid growth stage using Δ J ′. Abstract: In this work, fatigue crack growth behavior of commercial pure titanium (CP-Ti) under different load levels is carried out considering the degree of plastic deformation of crack tip. Results show that there are great differences in the stage of crack stable growth in different loading conditions. In the same crack growth rate, strain energy and plastic zone in high load ratio are much higher than those in low load ratio, when crack growth rate is low. However, when crack growth rate is high, the differences of strain energy and plastic zone between these two loading conditions are much smaller. More plastic strain energy will be consumed and a wider range of plastic deformation in crack tip will be required in the high load amplitude. It seems that Δ K and Δ J cannot describe these phenomena, while Δ J ac and Δ J ac ′ proposed in this paper may be more suitable to describe these phenomena in the fracture surface. In different loading conditions, at the late stage of crack growth, the fracture morphologies are all dimples. The data in all the conditions obey the Paris' law mode, with the same coefficient and index in the rapid growth stage using the parameter Δ J ac ′ .