Document Type

Article

Publication Date

1-1-2012

Publication Title

Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science

Abstract

Fatigue crack growth mechanisms of long cracks through fields with low and high residual stresses were investigated for a common structural aluminum alloy, 6061-T61. Bulk processing residual stresses were introduced in the material by quenching during heat treatment. Compact tension (CT) specimens were fatigue crack growth (FCG) tested at varying stress ratios to capture the closure and Kmax effects. The changes in fatigue crack growth mechanisms at the microstructural scale are correlated to closure, stress ratio, and plasticity, which are all dependent on residual stress. A dual-parameter ΔK-Kmax approach, which includes corrections for crack closure and residual stresses, is used uniquely to connect fatigue crack growth mechanisms at the microstructural scale with changes in crack growth rates at various stress ratios for low- and high-residual-stress conditions. The methods and tools proposed in this study can be used to optimize existing materials and processes as well as to develop new materials and processes for FCG limited structural applications.

Volume

43A

Issue

1

First Page Number

87

Last Page Number

107

DOI

10.1007/s11661-011-0879-5

Publisher Statement

Copyright 2012,, ASM International. This paper was published in Metallurgical and Materials Transactions A-Physical Metallurgy and Materials Science Vol. Iss. 1 pp. 87-107 and is made available as an electronic reprint with the permission of,, ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.

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