What is a common problem when welding aluminum using GTAW?

When welding aluminum using Gas Tungsten Arc Welding (GTAW), a significant issue is the formation of brittle intermetallic compounds. Aluminum, when welded, can react with certain alloying elements—particularly those found in some filler metals and the base material itself—leading to the creation of these hard and brittle phases. These intermetallic compounds can adversely affect the mechanical properties of the weld, including reducing ductility and toughness, which can lead to premature failure of the welded joint.

Understanding the chemistry of aluminum and the potential for these reactions helps welders choose appropriate filler materials and control welding parameters to minimize the formation of these detrimental compounds. This knowledge is crucial to securing reliable welds in aluminum structures, particularly those subjected to dynamic loads or harsh environments.