|About this Abstract
||MS&T23: Materials Science & Technology
||Interface-mediated Phenomena in Structural Materials
||Investigating the Deformation Mechanisms for Allvac 718Plus Superalloy Containing Bi-modally Distributed γ' Precipitates
||Geeta Kumari, Carl J. Boehlert, M Sundararaman, S Sankaran
|On-Site Speaker (Planned)
||Carl J. Boehlert
Alloy Allvac 718Plus is a relatively new superalloy primarily strengthened by the γ' (L12) phase. The dominant deformation mechanism varies with the size and distribution of the γ' precipitates. When the γ' precipitates are larger, dislocations tend to bow around them, whereas when the γ' precipitates are smaller, the dislocations tend to shear through them. Unimodal precipitate sizes were obtained through isothermal aging. A bimodal γ’ precipitate distribution was developed using a two-step aging treatment (900℃ for 2h then 720℃ for 10h), which resulted 14 nanometer and 55 nanometer precipitates on average. Transmission electron microscopy was performed on heat treated samples which underwent room-temperature tensile experiments and particle-dislocation interaction were studied. Existing empirical formulas were modified to predict the deformation mechanisms in the bimodal microstructures. Both a description of the microstructural evolution during the heat treatments and the deformation behavior differences between the bimodal and unimodal microstructures will be presented.