John Bohling is a Ph.D. candidate in the Department of Materials Science and Engineering and is working within the Materials Joining Group (MJG) under the direction of Dr. Carl Lundin. Prior to receiving his B.S. degree in Materials Science and Engineering from the University of Tennessee in December 2010, Mr. Bohling worked in the MJG for several semesters as an undergraduate research assistant, culminating in an undergraduate thesis with Dr. Lundin entitled “Development of Optimum Welding Procedures for In SituWeld Replacement for Main-Steam Piping.”
Mr. Bohling has been involved in several research areas with the Materials Joining Group, including microstructural characterization of creep-damaged, submerged-arc weldments in 1.25Cr-0.5Mo steels for steam piping, microstructural characterization and investigation of Type IV creep behavior of 9Cr-1Mo-V-Nb (P91) steels, high temperature hydrogen attack of C-0.5Mo steels, weldability investigations of high entropy alloys (HEAs) such as AlxCoCrFeNi, and dissimilar resistance spot welding of aluminum to steel using HEA interlayers. For his M.S. degree, his work centered on a 20Cr-32Ni-1Nb heat-resistant austenitic stainless steel casting alloy (ASTM A351 Grade CT15C), which is used for outlet headers and manifolds in hydrogen reformers. Weldability problems with this alloy have been reported during repair welding of service-exposed material, primarily as the occurrence of cracking in the base metal heat-affected zone (HAZ). Mr. Bohling’s research focused on Gleeble hot ductility testing together with microstructural characterization to evaluate the HAZ liquation cracking susceptibility of CT15C materials provided by an industrial sponsor (Air Products and Chemicals Inc.). Mr. Bohling successfully defended his M.S. thesis in July 2016, has passed his Ph.D. qualifying exams, and completed all the necessary coursework. Mr. Bohling is finalizing his Ph.D. research under the guidance of Dr. Lundin, focusing on Type IV creep behavior in P91 steel weldments.
During his time with the MJG, Mr. Bohling has worked as a teaching assistant in several undergraduate classes taught by Dr. Lundin, including Welding Metallurgy, Materials Processing, and the two-semester MSE senior course sequence, Materials Selection in Design (required for obtaining a minor in MSE) and Materials Selection (the MSE Capstone course). Mr. Bohling’s duties have included course organization and planning, proctoring and grading exams and reports, setting up laboratory sessions, and assisting the students with planning of experiments, sample preparation, and microstructure analysis for their group projects. In 2013, he received the MSE Departmental Student Award for Excellence in Service in recognition of his efforts.