David Gandy

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David Gandy
Electric Power Research Institute
"Comparative Thermal Aging Effects on PM-HIP and Forged Inconel 690" Keyou Mao, David Gandy, Janelle Wharry, JOM Vol. 70 2018 2218-2223 Link
"Thermal Aging and the Hall–Petch Relationship of PM-HIP and Wrought Alloy 625" Janelle Wharry, Keyou Mao, David Gandy, Elizabeth Getto, JOM Vol. 71 2019 2837 Link
Powder metallurgy with hot isostatic pressing (PM-HIP) is an advanced alloy processing method capable of fabricating complex nuclear reactor components near-net shape, reducing the need for machining and welding. For heat exchangers and steam generators, thermal aging of PM-HIP materials must be comparable or superior to conventional castings or forgings. This study compares thermal aging effects in PM-HIP and wrought alloy 625. Isothermal aging is carried out over 400–800°C for 100 h. Both PM-HIP and wrought materials have equiaxed grains with a uniform orientation distribution. The PM-HIP material has finer grains than the wrought material at all aging conditions. Both PM-HIP and wrought materials have a comparable hardness and modulus measured by nanoindentation. Hardness remains unchanged with aging except the wrought material aged at 800°C, which exhibits softening. Overall, PM-HIP alloy 625 responds comparably to wrought alloy 625 and is superior at 800°C. Results are used to calculate a Hall–Petch coefficient.
"Neutron Irradiation of Nuclear Structural Materials Fabricated by Powder Metallurgy with Hot Isostatic Pressing" David Gandy, Donna Guillen, Janelle Wharry, 2017 ANS Annual Meeting [unknown]