Fatigue damage mechanisms of thin brazed aluminium alloys used in car heat exchangers

摘要

In this work, a detailed characterization of the cyclic damage mechanisms in car heat exchangers has been undertaken in order to improve their reliability. The studied material is a very thin (<0.3 mm) aluminum sheet composed of 3 layers (4XXX/3XXX/4XXX), brazed in conditions similar to those of real components in order to obtain representative metallurgical and surface conditions in the fatigue samples. Fatigue tests at constant stress amplitude have been performed at room temperature, 120℃ and -30℃ in order i) to characterize the cyclic resistance of the studied materials and ii) to study the effect of temperature on the fatigue damage mechanism. The mechanisms leading to failure have been studied by optical microscopy, X-ray tomography and SEM-EBSD.