More Durable Pin Tools for Friction Stir Welding

This SBIR Phase I project will develop a novel processing method for W-Re alloys that will allow for higher performance pin tools for use in friction stir welding (FSW). A solid state process, FSW is fast becoming the process of choice for the manufacture of lighter weight aerospace structures.nbsp; As such, it is being considered as an essentially complementary joining capability for on-orbit and space environments. Pin tool technology especially for higher temperature FSW continues to be a major challenge and will limit usage in space if not further advanced. An ideal pin tool should have high toughness, good strength, excellent wear resistance, and be chemically inert at welding temperatures. Tungsten-based tools have good fracture toughness, but are also very expensive and experience severe wear and degradation during high temperature welding. A greatly improved, more cost-effective, and near-net process was developed to process pure W components with refined microstructures. If successfully applied to W-Re alloys to enhance the properties, higher performance pin tools may be possible.