2022 Technical Division Student Poster Contest: SMD 2022 Technical Division Undergraduate Student Poster Contest
Program Organizers: TMS Administration
Monday 5:30 PM
February 28, 2022
Room: Exhibit Hall C
Location: Anaheim Convention Center
SPU-10: Correlating Grain Boundary Energy to Abnormal Grain Growth Using Atomic Force Microscopy: Molly Kole1; Bryan Conry1; Prabal Tiwari1; William Burnett1; Amanda Krause1; 1University of Florida
Abnormal grain growth (AGG) is a phenomenon in which a fraction of grains grow faster than their neighbors leading to bimodal grain size distribution. Concurrent work has revealed that AGG is suppressed in textured alumina. It is hypothesized that texturing samples reduces overall AGG by greatly increasing the fraction of preferentially oriented grain boundaries, reducing the overall driving force for AGG. In this study, CaO-doped alumina was slip cast in a magnetic field to induce crystallographic texturing, and heat treated out of the field for different time periods at 1600˚C. Atomic force microscopy is employed to measure the dihedral angle of thermally etched grain boundaries, which can then be used to determine relative grain boundary energy. This investigation will compare microstructural evolution and corresponding relative grain boundary energies in identically processed textured and non-textured alumina.
SPU-11: Model Based Control of Microstructure for Additive Manufacturing 316L Stainless Steel: Matthew Michalek1; Daniel Moser1; Theron Rodgers1; 1Sandia National Laboratories
Laser powder bed fusion (LPBF) process parameters directly affect microstructural properties such as grain size and eccentricity which play a significant role in local and global stress/strain behavior. A preliminary process parameter to microstructure optimization algorithm was developed based on SPPARKS kinetic Monte-Carlo (kMC) simulations to begin controlling microstructural properties of additively manufactured 316L micro-scale geometries. Sensitivity analyses performed on laser power, laser speed, laser radius, and time between hatches, show influences on microstructure consistent with experimental data. Dividing Rectangles (DiRECT) method optimization show laser power and speed alone contribute to a 25% decrease in grain size. Wait time and laser radius show contributions of a 0.1% added decrease. In the future, the process and algorithm can be used to: (i) quantify mechanical performance uncertainty due to microstructure, and (ii) design microstructures for generalized additively manufactured part geometries against a mechanical environmental response based on crystal plasticity simulations.
SPU-12: Quantitative Analysis of Microstructure in the Ti-6Al-4V Alloy Using Scanning Electron Microscopy: Sydney Fields1; Dian Li1; Yufeng Zheng1; 1University of Nevada, Reno
Titanium alloys are critical structural materials with excellent comprehensive properties such as high specific strength, excellent toughness, and high corrosion resistance. These properties of titanium alloys can be tuned by the manipulation of microstructure evolution during a variety of heat treatment. In this work, we used the advanced scanning electron microscopy (SEM) and MIPAR image analysis software to quantitatively study the microstructural evolution in the Ti-6Al-4V (wt.%, Ti-64) alloy. The Ti-64 alloy samples were heat treated at 1000°C for 30 mins and then cooled to room temperature using different cooling methods, including water quenching, air cool, or furnace cool. The bimodal α microstructure, martensitic microstructure, and colony α microstructures have been characterized using SEM backscattered imaging. The morphology, size and fraction of each α microstructure have been quantified using MIPAR. This work has been supported by the University of Nevada Reno seed grant.