Abstract
The lattice misfit and diffraction elastic constants in hot rolled polycrystalline Co-7Al-5W-2Ta and Co-6Al-6W-2Ti (at.%) are measured using neutron and synchrotron X-ray diffraction. The misfit in the two alloys was found to be +0.67 and +0.59%, using neutron diffraction at HRPD. The misfit was found to increase with temperature, as in Ni superalloys. This implies that the amount of coherency strengthening increases with temperature. The diffraction elastic constants measured show that the γ ' phase is less stiff than the γ matrix in all orientations, which means that load shedding will occur to the γ phase.
Original language | English |
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Pages (from-to) | 201-208 |
Number of pages | 8 |
Journal | Materials Science and Engineering A |
Volume | 613 |
Early online date | 22 May 2014 |
DOIs | |
Publication status | Published - 8 Sept 2014 |
Funding
The authors would like to acknowledge the financial support provided by Rolls-Royce plc and EPSRC (UK) under the DHPA scheme (HY) and by Grants EP/H004882/1 (DD, NGJ, JC, VAV) and EP/H500375/1 (HJS, NGJ). Useful conversations with Mark Hardy at Rolls-Royce plc. are also acknowledged, as is the provision of beamtime by STFC (UK) at Diamond and ISIS and at SNS, ORNL by the Scientific User Facilities Division, Office of Basic Energy Sciences, Department of Energy (USA).
Keywords
- Co-Al-W superalloys
- elastic behaviour
- neutron scattering
- synchrotron X-ray diffraction