Partners:
Natural Sciences and Engineering Research Council of Canada (NSERC)
GKN Sinter Metals
CANMET Materials
Dr. Paul Bishop (Lead), Dalhousie University
Dr. William Caley, University of Manitoba
Abstract - Sinter-forging (SF) is a near-net-shape manufacturing technology that affords high material utilization rates, tight dimensional tolerances, complex product geometries, minimal energy consumption, and maximized mechanical properties. As these traits present favourable techno-economics, this sophisticated approach has been utilized extensively in the cost-effective fabrication of high-performance automotive components for nearly five decades. While highly successful, all commercialized SF technologies are presently restricted to the processing of heavy ferrous powders alone. This limitation presents challenges in many automotive scenarios given the recent push towards vehicle light weighting. In this sense, there is a clear global preference for the utilization of light metal alloys as these represent an important means to reduce vehicular weight thereby improving fuel economy and lowering greenhouse gas emissions. To address this technological gap, academics from Dalhousie University and the University of Manitoba are actively collaborating with engineers at GKN Sinter Metals and the federal research facility Canmet Materials Technology Laboratory to develop industrial SF technologies specifically designed for aluminum-based powders. In doing so, autonomous advances developed by the team in prior initiatives are now being unified to commission an entirely new family of novel aluminum-based materials specifically designed for SF technology. Focal areas of research include the optimization of alloy chemistry, the incorporation of ceramic particulates, thermo-mechanical working, material characterization, and industrial-scale SF operations. The net result will be a completely new paradigm of light weight SF materials and processes that will enable GKN to commercialize a new frontier of automotive components in Canada with a cascading impact on the Canadian automotive sector at large via gains at OEMs that implement the outcomes (enhanced performance, improved profitability, reduced emissions) and the array of Canadian companies that supply GKN with the raw materials and processing equipment needed to accommodate the associated increase in production capacity.
Partners:
Natural Sciences and Enigneering Research Council of Canada (NSERC)
GKN Sinter Metals
Dr. Paul Bishop (Lead), Dalhousie University
Abstract - Alloyed and tool steel powders are typically utilized in additive manufacturing (AM) to create tooling for conventional material forming technologies. The preferred feedstock is currently gas atomized powder that is fully prealloyed. While such materials perform well in an AM context, they are economically disadvantaged by production high costs. This issue can be largely overcome by utilizing alternate methods of powder production. The technology of interest in this initiative is water atomization. In this context, water atomized tool steel powders are being produced, classified and then processed by means of binder jet printing. The sintering behaviour of the printed specimens is optimized through an array of thermal analysis techniques coupled with bulk specimen production and mechanical/physical property characterization.
Partners:
Natural Sciences and Engineering Research Council of Canada (NSERC)
Dr. Paul Bishop (Lead), Dalhousie University
Dr. Adrian Gerlich, University of Waterloo
Abstract - The fabrication of automotive components by means of aluminum powder metallurgy (APM) technology has advanced significantly over the last decade. APM offers a number of key advantages including favourable techno-economics, low energy consumption, near-net-shape processing, and material versatility. As such, it is now the preferred means of producing many automotive parts in high volumes including camshaft bearing caps, transmission retainer rings, and reaction carriers. To expand the scope of commercial applications for APM products there exists an urgent need for the the development of joining technologies designed to bond APM components to themselves and/or conventionally processed alloys. In this initiative, friction stir welding is being explored as a potential candidate to fulfill this technological gap.
Partners:
Natural Sciences and Engineering Research Council of Canada (NSERC)
GKN Sinter Metals
Kymera International
Dr. Paul Bishop (Lead), Dalhousie University
Abstract - The focus of this research initiative is aluminum powder metallurgy (PM) processing. This is a near-net-shape metal forming technology wherein aluminum-based powders (and powdered forms of the desired alloying additions) are directly manipulated into geometrically complex components through a sequence of powder compaction, liquid phase sintering, and secondary operations (sizing, heat treatment, etc.). Aluminum PM has advanced steadily in recent years principally through the development of new alloys that exhibit a high sintered density (>99%) and in turn, significant improvements in mechanical properties relative to the out dated conventional blends originally devised over 40 years ago. While these next generation materials open many new applications for aluminum PM processing, new challenges have arisen as well including non-uniform shrinkage during sintering and a heterogeneous distribution of alloying elements in the sintered product. These issues stem from the intense densification behaviour and the use of elemental/master alloy powder mixtures as the feedstock respectively. To mitigate these constraints, a concept referred to as "hybrid alloying" was devised whereby the particles of aluminum are prealloyed with select alloying elements that are known to have a low diffusion rate in aluminum yet form secondary phases that are hard, thermodynamically stable, and highly resistant to thermal coarsening. Other alloying additions that either catalyze the sintering response and/or diffuse quickly into a homogenous state in aluminum are still added as elemental/master alloy forms so as to maintain compressibility and intense densification behaviour.
Partners:
Natural Sciences and Engineering Research Council of Canada (NSERC)
VLN Technologies
GKN Sinter Metals
Dr. Kevin Plucknett (Lead), Dalhousie University
Dr. Paul Bishop, Dalhousie University
Dr. Ted Monchesky, Dalhousie University
Abstract - Surface modification of metallic alloys is an important method for improving properties such as fatigue, wear resistance, and even the corrosion susceptibility. Traditionally, this can be achieved by shot peening or grit blasting, while laser shock peening techniques are also now available. Recently, a novel ultrasonic pulsed waterjet manufacturing technique has been developed by VLN Advanced Technologies (Ottawa, ON). This method allows precision metal cutting and controlled removal of surface coatings (e.g., hard chromium plating). However, it has also been demonstrated that surface peening may be possible, with the waterjet technique being much more environmentally friendly, and physically cleaner, than conventional shot peening. This research, in collaboration with both VLN and GKN Sinter Metals, investigates the fundamental physical mechanisms operating during ultrasonic waterjet peening, particularly in terms of potential cavitation phenomena, and the associated materials interactions. The effects of waterjet peening are being investigated for various aluminium, iron and titanium alloys, fabricated using either powder metallurgy or additive manufacturing, and compared to conventional wrought alloy variants; materials are of great importance to the aerospace and automotive industries within Canada.
Completed Research Initiatives:
Copyright, Dalhousie Particulate Material Research Group, 2019