|
|||||
|
|
Thermomechanical processing of a nickel-base superalloy powder compact |
|
| Authors: | AY Kandeil J-PA Immarigeon W Wallace MC de Malherbe |
| Affiliation: | 1. Faculty of Engineering, University of Qatar, PO Box 2713, Doha, Qatar;2. The National Aeronautical Establishment, National Research Council of Canada, Ottawa, Ontario, K1A OR6, Canada;3. The Mechanical and Aeronautical Engineering Department, Carleton University, Ottawa, Ontario, K1S 5BS, Canada |
| Abstract: | Some means by which the grain size and flow strength of nickel-base superalloy powder .compacts can be controlled during processing have been examined. The compacts were prepared by hot isostatic pressing and their flow behaviour studied by constant true strain rate compression testing under conditions simulating isothermal forging. It was found that the selection of a finer starting powder results in slight lowering of flow strength at forging temperatures. Prior cold working of the compact by hydrostatic extrusion also leads to small reductions in strength at these temperatures. Both the . grain size and flow strength may change substantially during plastic deformation at forging temperatures. This depends on the conditions of strain rate and temperature. Under all the testing conditions examined this transient flow behaviour is followed by a stesdy state regime of flow during which neither the grain size nor the flow strength continue to change. These observations and their practical implications are discussed. |
| Keywords: | Powder metallurgy High temperatures Hot isostatic pressing Grain size Flow strength Nickel-base superalloys |