Interfaces and Phase Transformations: Poster Session
Sponsored by: TMS Phase Transformations Committee
Program Organizers: Arun Devaraj, Pacific Northwest National Laboratory; Matthias Militzer, University of British Columbia; Matthew Steiner, University of Cincinnati; Mohsen Zaeem, Colorado School of Mines; Yufeng Zheng, University of North Texas
Tuesday 10:00 AM
November 3, 2020
Room: Poster Hall
Location: MS&T Virtual
Computing the Free Energy and Mobility of Cylindrical Interfaces: Anqi Qiu1; Ian Chesser1; Elizabeth Holm1; 1Carnegie Mellon University
An interface is a planar defect that occurs at the intersection of materials with different structural parameters, such as different crystal orientations or phases. The free energy and mobility of interfaces are key parameters in determining microstructural evolution, including grain growth in solids and melting and solidification processes at solid-liquid interfaces. The free energy and mobility of a flat solid-liquid interface have been determined in by applying the synthetic driving force (SDF) molecular dynamics method. In this work, we extend the SDF scheme to determine the free energy and mobility of cylindrical grain boundaries and solid-liquid interfaces, in order to investigate the thermodynamics and kinetics of the interfaces.
Refining Alpha Microstructure via Dual-phase Interface and Twin Boundary in Beta Titanium Alloys: Dian Li1; Xing Zhang2; Yiliang Liao2; Stoichko Antonov3; Yufeng Zheng1; 1University of Nevada, Reno; 2Iowa State University; 3Max Planck Insitut fur Eisenforschung GmbH
The microstructural evolution in beta titanium alloys can be significantly modified using accurately designed thermomechanical treatment. The size, morphology and distribution of the hcp alpha precipitates in the bcc beta matrix can be tuned accordingly. By introducing dual-phase interface and twin boundary into the interior of beta grains, e.g., the pre-formed O”/beta interface and deformation twinning boundary, various fine-scale intragranular alpha microstructures can be produced. In this work, the structure and composition near the pre-formed O”/beta interface were investigated using advanced electron microscopy and atom probe tomography in a beta titanium alloy, Ti-5Al-5Mo-5V-3Cr (wt.%, Ti-5553). The microstructure near the boundary between the novel {10 9 3}<3 3 1> type deformation twin and beta matrix was characterized. The influence of pre-formed O”/beta interface and deformation twinning boundary on the formation of various fine-scale intragranular alpha microstructures produced in Ti-5553 using different thermomechanical treatments will be introduced.