Research
RESEARCH INTERESTS AND TOPICS
- foams
- ceramic and metal matrix composites
- aluminum and titanium
- powder metallurgy
- non-oxide/metal ceramic joining
- joining and brazing
- fundamentals of metal-ceramic interactions
- processing, sintering and properties of nitride ceramics
- melt extraction of oxide fiber ceramics
- metal and ceramic coatings.
FIVE MOST SIGNIFICANT
RECENT CONTRIBUTIONS IN RESEARCH
Aluminum MMCs, Infiltration and Wetting Studies
Extensive expertise exists on liquid aluminum infiltration into ceramic preforms to produce MMCs. This work has made a significant contribution in the area of metal-ceramic interaction studies and wetting as well as composite formation. More recent research has involved coating of ceramic particles to enhance processing. This research has been extended to the study of wetting on several types of ceramics and has been used to understand the processing and porosity formation in Al-Si foundry alloys in collaboration with France.
Joining and Brazing
Research over several years in joining and interactions has led to a series of papers that have made a major contribution to the understanding of non-oxide ceramic-metal interactions. Novel techniques using reactive metals such as Ti and Ti-Cu combinations, to create transient liquid brazing to produce high temperature joints with iron aluminide alloys has opened up a new opportunity for this research. More recently work is being refocused on conventional welding and brazing of light metals and superalloys applying the expertise developed in the group over my career.
Titanium Metal-Matrix Composites
A significant outcome of this work was the understanding of the process control in relation to microstructural and mechanical property improvements of Ti MMCs. TiC particle reinforcements are incorporated into Ti-6V-4Al alloys using both sintering and thermo-mechanical processing. The relationship between the TiC and Ti2C phase was elucidated by neutron diffraction studies (AECL) and using novel, low-voltage field emission SEM studies.
Aluminum Nitride Ceramics
Aluminum Nitride has been studied for electronic thermal management due to its excellent thermal properties. This work involves novel high temperature neutron diffraction studies in collaboration with NRC and AECL. Major insight has been achieved into understanding the sintering mechanisms and their effect on thermal conductivity as well as phase equilibria of oxide-nitride systems (with Thompson of Queens/RMC).
Melt Extraction of Oxide Fibres
This work focuses on the use of a unique technology to fabricate fine fibres of alumina-based ceramics using melt extraction of eutectic oxides on a sharpened wheel. Collaboration was established with DLR, the German Aerospace Establishment in pursuing this technology for ceramic matrix composites. More recent work has shown that Al2O3-Y2O3 fibres can be produced using this technique and that they have potential as photonic materials due to their low absorption in the infrared region. A significant contribution to the understanding of crystallization kinetics of these rapidly solidified fibres has evolved from this study.
Recent Collaborators
- L-P Lefebvre, IMI-NRC, foams
- R. Panneton, University of Sherbrooke, Aluminum Foams
- A.R. Kennedy, University of Nottingham, UK, Aluminum foams and MMCs.
- R. Gauvin and J-L Meunier, McGill University, aluminium MMCs produced with carbon nanotubes, co-supervision.
- M. Jahazi and J-P Immarigeon, AMTC/NRC, joining and aerospace materials, co-supervision.
- M.D. Pugh, Concordia University, Metal –ceramic joining, composites and co-supervision.
- W.F. Caley, Dalhousie University: Co-supervision of graduate students.
- W.T. Thompson, RMC, Queens: Co-investigator on Strategic Project.
- J.E. Gruzleski, McGill: Oxidation of molten Al and Microporosity in Al foundry alloys.
- Westaim/Zimarc Inc.: AlN ceramics fore electronic substrates.
- J. Root, CRNL/AECL: Neutron diffraction in residual stress studies in ceramic/metal bonds, Ti-TiC composites, structural oxygen in AlN, cosupervision.
- E. Bedolla and Carlos Leon, Instituto de Investigaciones Metallurgicas, Universidad Michoacana, Mexico, Melt Infiltrated Composite Materials.