Abstract
The inhomogeneity and anisotropy of mechanical properties of age-hardenable Al-alloys extrusions studied by tensile and compression tests are largely described in recent literature. The aim of the present paper is to describe the main features of the anisotropy and inhomogeneity of fatigue lives and to compare them with those observed recently in the same alloys under tensile tests. The paper deals with several age-hardenable alloys from the systems: Al-Li, Al-Cu-Mg, Al-Zn-Mg-Cu and Al-Mg-Si. The high-cycle fatigue of two particular model extruded shapes of large-sized cross-section was investigated. The results of the tests indicate that the fatigue lives of the extrusions prepared from all investigated alloys are remarkably inhomogeneous and anisotropic.

Key words
aluminium alloys, extrusion, inhomogenity, anisotropy, fatigue properties, mechanical properties, texture, solid solution decomposition

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