Abstracts zu Vorträgen
Gastvortrag am 04.07.2014
Solid State Processing and Advanced Strength, Wear and Ballistic Materials
Prof. Michel Nganbe, University of Ottawa, Department of Mechanical Engineering
ABSTRACT: Since its first steps in 3000 BC, start of mass production in the 19th century and the introduction of mechanical alloying in the 1960s-1970s, the powder metallurgy technique has made steady progress and has become the process of choice for some of the most advanced materials. Two of the most prominent applications are wear and armor components. For instance, components used in mining, transportation and processing of oil sands suffer heavy wear damage resulting in frequent failure, down-time and loss of revenue. Therefore, we investigated the increase of wear resistance using novel nanostructured composite coatings. The hardness, fracture toughness and wear resistance were proven substantially higher compared to conventional steels and microcrystalline coatings. In the field of armor materials, the current design made of a ceramic front plate attached to a metal backing plate can result in ceramic failure due to impedance effects. Therefore, we research on functionally graded particle and fiber reinforced composites in which reinforcement content and properties gradually vary from the front impact face to the back face. This effectively eliminates impedance effects at the ceramic/metal plate interface. Our research initially focused on aluminum matrix composites manufactured by squeeze casting and show promising results that will be expanded to other base materials. Also, ceramics are today uncontested candidates for front plates of armors. We study novel armor ceramics with respect to microstructure, hardness, density, fracture toughness, fracture strength and fracture mode. The results indicate that appropriate second phase particles and porosity can significantly influence armor ceramic performance.