Fatigue crack propagation in ultrafine grained Al–Mg alloy

• Published in: International journal of fatigue Vol. 27; no. 10; pp. 1164 - 1169
• Main Authors: Pao, P.S., Jones, H.N., Cheng, S.F., Feng, C.R.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01.10.2005; Elsevier Science
• Subjects: Aluminum; Applied sciences; Exact sciences and technology; Fatigue; Fatigue crack growth; Fatigue crack growth threshold; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Microstructure; Ultrafine grained material; Fatigue crack growth; Microstructure; Aluminum; Fatigue crack growth threshold; Ultrafine grained material; Mechanical properties; Fine grain structure; Fatigue; Fatigue threshold; Fatigue crack; Crack propagation
• ISSN: 0142-1123; 1879-3452
• DOI: 10.1016/j.ijfatigue.2005.06.027

The fatigue crack growth rates in ultrafine grained (UFG) Al–7.5Mg were investigated and were compared to those observed in powder-metallurgy (P/M) Al–7Mg and ingot-metallurgy (I/M) Al–7Mg. Fatigue crack growth rates in UFG Al–7.5Mg are significantly higher than those of P/M Al–7Mg, which, in turn, are significantly higher than those of I/M Al–7Mg. The fatigue crack growth threshold is the lowest in the UFG Al–7.5Mg, followed by P/M Al–7Mg, and is the highest in I/M Al–7Mg. The higher fatigue crack growth rates and lower thresholds in UFG Al–7.5Mg may be attributed to the much smoother fracture surface morphology and lower roughness-induced crack closure and crack deflection.