Effect of Pre-welding Heat Treatment on the Mechanical Properties of Friction Stir Welded Al-4 wt.%Cu Alloys

摘要

This research investigates the welding of aluminum alloy Al-4wt.%Cu using friction stir welding (FSW). Besides the traditionally studied FSW process parameters (i.e., pin rotational and transverse speeds), this work addresses the effects of two pre-welding heat treatment conditions (annealing vs. age hardening) on the resulting weld joint. A set of experiments was carried out to assess joint quality under different levels of process parameters with specimens either annealed or age hardened prior to welding. The results revealed that age-hardened specimens prior to welding possessed higher hardness, higher penetration, and less wear rate among joint zones compared to the annealed ones and base metal. Moreover, the best joint quality was found to be obtained at higher welding and rotational speed regardless of pre-welding heat treatments. Findings of interest to industry, it is economically recommended to weld these types of high-strength aerospace aluminum alloys after age hardening.