CAREER: Amorphization of Aluminum and Aluminum Alloys

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

TECHNICAL SUMMARY: Strong industrial demand has stimulated the research and development of nanostructured or amorphous aluminum (Al) alloys with improved ductility, strength, fracture toughness and fatigue resistance. However, the methods currently employed, such as rapid solidification and severe plastic deformation, offer limited control over the possible chemistry or microstructure of the produced Al alloys. While searching for the new electrode materials for batteries, several research groups world-wide have recently discovered the phenomenon of electrochemically-driven solid state grain refinement and amorphization of semiconductors and metals, which takes place during the room temperature electrochemical alloying and de-alloying of materials with Li. The proposed project aims to harness this novel method to modify the morphology of Al and Al alloys in order to enhance their mechanical properties. Replacing Li with Mg was hypothesized to greatly enhance the amorphization efficiency. This potentially transformative and versatile technology does not require elaborate plastic deformation techniques. It is expected to circumvent the limitations of state-of-the-art technology and broaden the range of the attainable properties of Al alloys. To gain a fundamental understanding of electrochemically-driven amorphization, the proposed project will systematically investigate the influence of relevant physical parameters on the electrochemical alloying and de-alloying of Al alloys. The influence of the initial metal microstructure, orientation and composition on the electrochemical alloying/de-alloying processes and the microstructure of the obtained Al alloys will be studied. The project will also identify how post-annealing processing changes the microstructure and mechanical properties of Al alloys and will include a systematic study of the structure-property relationships for Al alloys as a function of the grain size distribution, density and chemical composition. The proposed study will establish guidelines for the formation of a wide range of metallic glasses via electrochemical amorphization routes. NON-TECHNICAL SUMMARY: Aluminum (Al) and Al alloys are critically important lightweight materials for construction and transportation. The research and development of nanostructured or amorphous Al alloys leads to significant improvements of their mechanical properties. The proposed project aims to investigate a novel method of electrochemically-driven grain refinement and amorphization of Al alloys, which takes place at room temperature. This study may open the door to a new direction in science, where electrochemical methods are used to overcome the limitations of traditional metallurgy. Lighter weight, higher plasticity, fracture toughness, specific elastic modulus, corrosion resistance, hardness and strength are some of the advantages this new revolutionary direction in lightweight metal processing can produce. The graduate and undergraduate students working on this project will have an opportunity to learn and develop novel processing techniques, will enhance their communication skills and will be well prepared to solve new challenges in their future engineering careers. Student presentations at local, national and international meetings will help to disseminate the important results of structure-property relationships in lightweight metals to the general public. The PI will involve teachers from high schools with large minority populations in the proposed research project and will help them to develop new educational modules and implement them in the physics and chemistry curriculum. This activity will help to educate minority students about metallurgy and materials science and excite their interest in engineering careers. The results of the research will be incorporated into one undergraduate and two graduate classes.