Microstructure dependent fatigue crack growth in aged hardened aluminium alloys

• Author(s): Borrego, L. P. ; Costa, J. M. ; Silva, S. ; Ferreira, J. M.
• Date: 2004
• Persistent ID: http://hdl.handle.net/10316/4249
• Origin: Estudo Geral - Universidade de Coimbra
• Subject(s): Aluminium alloys; Fatigue crack growth; Retardation; Microstructure; Crack closure; Overloads
• Document Type: Article
• Language: English

Description

Fatigue crack propagation tests in constant amplitude loading, as well as with single peak overloads, have been performed in AlMgSi1-T6 aluminium alloys with different Mn and Cr contents. Crack closure was monitored in all tests by the compliance technique using a pin microgauge. A moderate stress ratio and a strong material dependence effects on the fatigue crack growth were observed. These effects are discussed in terms of the different dominant closure mechanism (plasticity-induced closure or roughness-induced closure). Roughness-induced closure dominates crack closure in the alloys with higher contents of Mn and Cr elements. In the alloy with a lower content of these elements, plasticity-induced closure is dominant. When roughness-induced closure is the prime pre-overload closure mechanism, the retardation effect is decreased in comparison to when plasticity-induced closure is dominant. http://www.sciencedirect.com/science/article/B6V35-4CPD73M-3/1/e77472d32013689741e1021b5b6ffcce