|About this Abstract
||MS&T21: Materials Science & Technology
||Probing Defect Properties and Behavior under Mechanical Deformation and Extreme Conditions
||Local Phase Transformation Strengthening in Ni-based Superalloys
||Ashton J. Egan, Fei Xue, Timothy Smith, Longsheng Feng, Shakthipriya Baskar, Emmanuelle Marquis, Yunzhi Wang, Maryam Ghazisaeidi, Michael Mills
|On-Site Speaker (Planned)
||Ashton J. Egan
In the intermediate temperature creep regime of Ni-based superalloys (~700 °C) deformation is dominated by planar defects and microtwinning, where deformation response is controlled by segregation events surrounding the leading partial dislocations. Of particular interest are alloys exhibiting Local Phase Transformation (LPT) along planar defects, a dynamic process whereby the alloy can be strengthened during service. The propensity for LPT strengthening depends on the relative ratio of η and/or χ formers, depending on active mechanisms, and in this study the LPT composition regime was explored with several commercial and novel alloys. Advanced characterization of the deformation mechanisms and LPT was accomplished by Scanning Transmission Electron Microscopy (STEM), Energy Dispersive X-Ray Spectroscopy (EDS), Atom Probe Tomography (APT), and SEM-based Electron Channeling Contrast Imaging (ECCI), while being supported by density functional theory (DFT) and phase field computational techniques. Understanding these complex phenomena is crucial in creating a homogenized constitutive creep model.