Understanding the Structure, Corrosion and Mechanical Behavior of Nanostructured Al-V Alloys Produced by High-Energy Ball Milling and Subsequent Consolidation

North Carolina State University, Raleigh NC

Investigators

Abstract

Developing stronger, lightweight, and durable materials is critical to address current technological challenges in many industries including automotive, aerospace, energy and infrastructure. The strength and durability of metallic materials is limited by the conventional compositions and manufacturing technologies. In particular, aluminum alloys suffer from corrosion susceptibility when subjected to processing techniques used to increase the strength of many alloys. The development of new aluminum alloys, with concurrent high strength and corrosion resistance, requires new scientific knowledge of the mechanisms that control corrosion and deformation behavior in these materials. This award supports fundamental research to uncover these mechanisms of degradation and strengthening. The investigation will also support the development of the knowledge base and workforce for the nation's future. The graduate and undergraduate students working on this research will be trained to address future technological challenges in a multidisciplinary setting. The outcomes of the research will help in developing teaching materials to support the nation's first undergraduate program in corrosion engineering at the University of Akron, and to support K-12 outreach activities to work with the local communities and high school students to increase STEM awareness. Use of aluminum (Al) alloys is limited in many applications due to their limited strength and deterioration of the corrosion performance with efforts made to increase their strength. Therefore, developing new Al alloys exhibiting ultra-high strength and excellent corrosion resistance is of paramount importance. It is hypothesized that grain refinement < 100 nm and extended solid solubility of Vanadium (V) in Al can improve mechanical and corrosion properties simultaneously. Nanocrystalline Al-V alloys with a wide range of V content will be produced using high-energy ball milling. The alloys will be exposed to various heat treatments for studying the thermal stability and creating a wide range of grain size, V solid solubility, and intermetallic distribution. The role of the microstructure on passivation, corrosion initiation and propagation processes, and mechanical properties will be studied using state-of-the-art material and surface characterization, electrochemical and mechanical testing techniques. This investigation will advance scientific understanding of the: 1) influence of the processing on the structure, corrosion and mechanical behavior of the nanostructured Al-V alloys, 2) role of nanocrystalline structure, intermetallics, and extended solid solubility of V on the corrosion and mechanical properties, and 3) phenomena leading to the simultaneous improvement in corrosion and mechanical properties. Fundamental understanding developed in this research will lead to a theoretical framework for the development of ultra-strong and corrosion resistant Al alloys. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.