Influence of Different Aging Times and Temperatures on Microstructural and Mechanical Properties of EN AW-6XXX Aluminum Alloys

Abstract

The heat-treatable EN AW-6005 and EN AW-6060 alloys are by far the most used alloys for manufacturing extruded parts for automotive, aerospace, food and healthcare industries. The strength of these alloys is usually achieved by T6 heat treatment, whose efficacy depends on the chemical composition and solubilization/aging times and temperatures. This study aims to evaluate the influence of aging parameters on the microstructural and mechanical properties of two extruded components made of the above-mentioned alloys and supplied by a healthcare company. Samples were drawn by both parts in as-received condition. Part of them was directly artificially aged at different aging times and temperatures, while the rest was subjected to tailored T6-type heat treatments. The microstructure was first analyzed by optical and scanning electron microscopy. The mechanical properties were then investigated by Brinell hardness and Vickers microhardness measurements. At last, all hardness data were compared to those obtained on specimens drawn from two other components made of the same alloys, which were heat-treated according to the parameters commonly used by the company. Based on the results, the microstructure of both components exhibited coarse grains plus lamellar and rounded intermetallic particles. Irrespective of the heat treatment route, no changes were detected in the microstructure. For each alloy, the heat treatment conditions that guarantee the best mechanical resistance were established.