|
7346 |
|
Thursday, May 05, 2022, Hall G1 10:20 AM HVOF/HVAF Spraying II |
|
Exploring miniaturized HVOF systems for the deposition and near net shape forming of Ti-6Al-4V |
|
Jörg Oberste Berghaus* / National Research Council Canada, Canada Maniya Aghasibeig / National Research Council Canada, Canada Phong Vo/ National Research Council Canada, Canada Alan Burgess/ Spraywerx Technologies Inc., Canada Peyman Khamsepour/ Concordia University, Canada Christian Moreau/ Concordia University, Canada Ali Dolatabadi/ University of Toronto, Canada |
|
The exceptional properties of Ti-6Al-4V of high strength, lightweight, corrosion resistance and machinability make it one of the most widely used alloys in in the aerospace industry. Significant efforts are underway to establish powder bed additive manufacturing (AM) technologies for Ti-6Al-4V. There are also increasing attempts to use thermal and cold spray to build near net shape parts with buildup rates orders of magnitude higher than powder bed. Thermal spraying, such as HVOF, can oxidize and degrade the alloy due to the high processing temperature. Lowering the flame temperature through inert gas addition in full-size HVOF systems is a possible approach to retain solid state deposition of the feedstock particles, thereby limiting oxidation and detrimental ?-case formation, while providing sufficient heat input for particle softening and plastic deformation at impact. Novel miniaturized HVOF systems, with spray jets of only a few millimetre in width, may further offer the possibility to improve the spatial resolution of the buildup for near net shape forming. The process parameter range and suitable feedstocks for solid state deposition of Ti-6A-4V, using the liquid fueled Praxair JPid 825 and the novel hydrogen fueled Spraywerx NOVA series will be discussed. Buildups at over 90% deposition efficiency generally yield as-sprayed porosities below 3% and hardness above 300 HV100gf. Attainable microstructures and oxygen content as a function of spray parameters will be delineated. Phase composition, ultimate tensile strength (UTS) and elongation to failure after recrystallization and beta annealing will be compared for selected samples produced by the miniature HVOF and a small-sized HVAF (Uniquecoat i7) system. |