Grain Boundary Engineering of High-Temperature Structural Alloys

1. Grain Boundary Engineering of High-Temperature Structural Alloys Carl Boehlert, Michigan State University, DMR-0533954 • Through controlled thermomechanical processing treatments, Grain Boundary Engineering (GBE) of the orthorhombic (O) phase in Ti-Al-Nb alloys can be achieved where the misorientation distributions at the grain boundaries can be altered through phase transformation. • When the O structure primarily transforms from the hexagonal close-packed (hcp) a2 phase, near 60° misorientations dominate. However, when the O phase is derived from the body-centered-cubic (bcc) structure, near 90°misorientations are prevalent. a The observations suggest that phase transformations play a dominant role in dictating the grain boundary character distribution (GBCD) for the Ti2AlNb intermetallic system. Controlling the phase transformations through thermomechanical processing treatments, which dictate the 2 and bcc volumes present, is considered a means to GBE O+bcc microstructures. This in turn is expected to be important to the resulting mechanical behavior. b Misorientation angle versus number fraction plots for microstructures which exhibited primarily (a) near-60°misorientations and (b) near-90°misorientations. Li, Wright, and Boehlert, Scripta Materialia, 51/6 (2004) 545-50; Li and Boehlert, Metallurgical Transactions, 2005, in print.

2. Scanning Electron Microscopy Education (SEMED) Outreach Program; DMR-0533954 The goal of this outreach program is to educate non-majors, high school students, and teachers about Materials Science and Engineering (MSE). The program is based on Scanning Electron Microscopy (SEM) education and involves hands-on instruction in use of a SEM.In its first two years, over 355 students have been taught by volunteers, including faculty, staff, graduate and undergraduate students. Some of the students then return to the program to perform a project for their high school science classes on samples they have prepared. Bolivar Richburg High School Science Students Performed Their 4th Quarter Research Project, titled “Life Beneath the Naked Eye”, through the SEMED Program. Visit http://semed.alfred.edu for details and to see the students’ interesting posters. Top: Undergraduate student, Daniel Burnett III, instructs two high school students during their hands-on learning session using the SEM. Bottom: High school students examined human, alpaca, and dog hairs and evaluated their size scales and presented their results in poster format.