M. A. Malik
The Journal of Mechanical Science and Technology, vol. 23, no. 5, pp.1261-1269, 2009

Abstract : In present study, as a basic step for modeling the fatigue behavior of an extruded Al alloy cylinder, the fatigue crack growth data of the alloy was collected in two orientations. Microstructural analysis revealed that the material had recrystallized grains and clusters of constituent particles aligned in the direction of extrusion. Fatigue life of the samples revealed a shorter fatigue life representing a higher fatigue crack growth rate in transverse direction. The Paris constants C and m were found to be 4 x 10-11 and 3.4 for the transverse orientation. The same constants were found to be 2 x 10-10 and 2.6 for the longitudinal direction. Post fracture analysis revealed that the topographical appearance of the fractured surfaces in two orientations was different. The mechanism of crack growth was the formation of striations. The present study revealed that the texture of the constituent particles created during extrusion process has a pronounced effect on the crack growth rate in two orientations.

Keyword : Aluminum alloy; Fatigue crack growth; Paris constants; Post-fracture analysis