Innovative Surface Modification for Aluminum, Magnesium and High Strength Steel Alloys to Enhance Corrosion Resistance

7xxx series aluminum alloys are widely used for structural components of aircraft such as wing spars due to their high specific strength. Unfortunately, tempering most 7xxx series alloys to peak strength results in susceptibility to stress corrosion cracking (SCC). Despite utilizing the best available surface treatments, SCC results in unscheduled maintainence of naval aircraft. QuesTek Innovations LLC, a leader in the emerging field of computational materials design, is uniquely suited to design an SCC-resistant, high-strength aluminum alloy for the aerospace industry. QuesTek has experience commerciallizing high-performance stainless and gear steel alloys, and QuesTek has developed extensive mechanistic process – structure and structure – property models specific to 7xxx series alloys. These models include custom thermodynamic and kinetic databases, well-calibrated microstructural evolution models utilizing PrecipiCalc software, and a validated, physics-based strength model. The overall goal of this SBIR program is to design and develop an advanced, high-strength aluminum alloy with improved SCC resistance compared to commercially available Al alloys. To demonstrate the feasibility applying Materials by Design® approach during Phase I, QuesTek plans to develop a qualitative model for SCC of aluminum alloys; design model alloys to achieve the 7075-T6 strength with maximum SCC-resistance; and produce and characterize these model alloy designs.