Grant: Discovery Grants Program - Individual

Depleting natural resources and increasing environmental concerns are current major challenges. In addition, increases in mobility, performance, speed and safety are constant demands. These challenges have made high-performance lightweight materials fundamental concepts of today's technology, particularly in automotive, aerospace and defence. Therefore, the proposed research program aims at developing lightweight, gradient, multiscale reinforced aluminium matrix composites using fibres, nanotubes and nanoparticles. A novel and cost efficient laminate squeeze casting technique will be developed. The required squeeze pressure will be achieved using primarily differences in thermal expansions of the set-up components with little to no need for presses or other compaction equipment. This enables easy technology transfer to industry. In this technique, thin pre-fabricated aluminium green layers melt and infiltrate the sandwiched fiber layers over short distances, minimising temperature and pressure drops that are challenges often encountered in standard liquid infiltration using 3D preforms. Research will focus on carbon fiber as primary reinforcement, while carbon and boron nitride nanotube will be studied as reinforcement of the fiber-matrix interface to improve bonding. Additional hardening of the aluminium matrix will be achieved using primarily Al2O3 nanoparticles introduced in the greens by mechanical alloying and powder metallurgy. Functional gradients will be introduced by varying the concentrations of reinforcements across the composite thickness. This will increase the efficiency of the composites by matching properties to specific load distributions across components. The composites will be characterised using optical and scanning electron microscopy as well as X-ray diffraction. Bend and impact testing will be used to study the strength, stiffness, impact fracture resistance and failure modes. To guide further improvements, relationships will be established between fabrication parameters, microstructure, and mechanical properties using physics-based, neural network, finite element and meshless modelling. The proposed research will have a major economic impact for Canada as the world's third largest producer of primary aluminium, with an annual output estimated at 3.2 million tonnes, exports totaling over $12.7 billion in 2017, and over 10,000 direct jobs for primary aluminium production alone. It aims at expanding Canada's capacity to manufacture value-added aluminium products. The emphasis is on new composites for highly demanding applications in automotive, aerospace and defence. Near pressureless fabrication aims at matching manufacturing practices which will facilitate industry adoption and increase the technological impact of metal matrix composites. Overall, the targeted high performance-to-weight ratios will contribute to increased efficiency, mobility and safety as well as to reduced energy consumption and environmental impact.