Grant: Collaborative Research and Development Grants

Nickel-based superalloys are used extensively for components in aircraft and land-based power generation gas turbines. Welding of these components during fabrication or repair can be problematic due to high susceptibility of some nickel-based superalloys to cracking in the heat affected zone (HAZ) during welding and post weld thermal treatments. A great deal of attention has been directed in the recent years toward research and development of improved welding techniques for difficult-to-weld superalloys. Laser beam welding offers the capability of joining thick metallic sections with extremely low heat input relative to those of conventional arc welding techniques, with resultant reduced HAZ size, minimal physical distortion and mechanical damage. A new generation of laser, Fiber laser, has recently become a major focus of attention due to its advantages of high-power, high beam quality, better stability and high-efficiency to produce precise, repeatable deep penetration welds at high speeds. These attractive characteristics prompted Standard Aero Ltd., a leading independent gas turbine engine repair service provider in Canada, to support the University of Manitoba in setting-up a collaborative research project on Fiber laser welding. The objective of the research is to study improvement in weldability of difficult-to-weld superalloys through a combined application of microstructural modification and advanced features of the emerging Fiber laser and hybrid laser-arc welding technology. The proposed project will involve development of procedures to modify pre-weld and as-weld microstructures and reduce welding stresses in order to prevent or minimize HAZ microfissuring and impart reliable high temperature mechanical properties in laser welded turbine components. Research efforts and investments in this field are justified by the large extent of gas turbine repair market, which is close to a $1 billion business in Canada. Support for the project would ensure that the Standard Aero Ltd. remain competitive and be able to attract further repair work from companies outside Canada. This will lead to increased business, jobs for Canadian engineers and the training of highly qualified personnel at the University.