Low anisotropy of fatigue crack growth in Al-5.8Mg-0.25Sc. (August 2019)

• Record Type: Journal Article
• Authors: Li, Mengjia; Shi, Yunjia; Pan, Qinglin; Zhang, Yu; Lu, Guangxi; Guan, Shaokang; Birbilis, Nick
• Is Part Of: International journal of fatigue. Volume 125(2019)
• Page Start: 170
• Page End: 178
• Publication Date: 2019-08
• Subjects: Al-Mg-Sc alloys -- Texture -- Fatigue crack growth -- Anisotropy; Materials -- Fatigue -- Periodicals; Materials -- Fatigue; Periodicals; 620.1122
• DOI: 10.1016/j.ijfatigue.2019.04.003
• Languages: English
• ISSNs: 0142-1123

Abstract

Highlights: Brass and S textures lead to larger Schmid's factor in the rolling direction (L–T). FCG resistance in L–T was increased by atypical fibrous structure. The cold-rolled-annealed samples show higher strengths and FCG resistance. The alloy shows low anisotropy of FCG behavior in the Paris region. Abstract: The fatigue crack growth characteristics of an Al-5.8Mg-0.25Sc(-0.4Mn-0.1Zr) alloy were investigated with regard to the loading direction. The cold-rolled and annealed samples show lower crack growth rates than hot-rolled samples at the same values of stress intensity factor (ΔK). The rolling (L–T) and transverse (T–L) directions exhibit different fatigue crack growth rates at the initial stage and unstable stage, but present similar behavior in the Paris stage. Results reveal that the Brass and S textures in Al-5.8Mg-0.25Sc alloy can lead to larger Schmid's factor and higher resolved shear stress in the rolling direction than in the transverse direction when the same value of stress is applied to the alloy, so the strength in the rolling direction is relatively lower and the fatigue crack growth rate of it is relatively higher in the initial stage. While the resistance to fatigue crack growth in the rolling direction was also increased by an atypical fibrous structure, consequently, the balance between the resolved shear stress and the resistance against fatigue crack growth related to the alloy orientation results in a unique anisotropy of fatigue crack growth behavior of Al-5.8Mg-0.25Sc alloy in the Paris region.