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Abstract

This research studies the effect of heat treatment (precipitation hardening) on fatigue life of two aluminum alloys (2024) and (7075). The alloy (2024) is hardening by natural aging, while the artificial aging is used to hardening the alloy (7075). Mechanical tests are performed to determine the mechanical properties such as yield stress, ultimate tensile strength, hardness and endurance limit of the
alloys. The specimens which used in the tests are divided into eight groups according to the type of alloy, type of heat treatment, and shape. Notched and un-notched specimens are used to perform the tests. The fatigue tests are performed for different type of specimens.
The equations of fatigue life estimation are determined according to data which is obtained from the fatigue tests and endurance limit is calculated by using these equations for each type of specimens.

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