13 ADVANCED MATERIALS & PROCESSES | OCTOBER 2023 Describe your education or career in relationship to the two disciplines of materials and mechanical engineering. Scott Carpenter: I graduated from the University of California, Berkeley with a double major in mechanical engineering and materials science and engineering; so these worlds were brought together for me through my education. In my professional career, I began working with shape memory alloys at Raychem in the late 1980s and continue to work with these materials today. I have worked with numerous other metals and alloys, as well as polymers, ceramics, and coatings throughout my career. My main focus has been on Nitinol processes and products. Nitinol is a highly non-linear, anisotropic, and path dependent material, and as such requires computer simulation for all but basic analyses. This material is sensitive to thermomechanical processing history; so, you cannot separate the processing and its impact on properties from the mechanical design. Understanding the mechanical aspects of these materials requires an understanding of how the crystallography works. Bertrand Jodoin: I have a bachelor’s degree in mechanical engineering with a specialization in aerospace and a Ph.D. in chemical engineering. As part of my undergraduate studies, I took two courses related to materials and numerous courses about mechanical engineering. While pursuing my Ph.D., I again took a few courses on materials. My dissertation was on the development of a DC plasma torch for coating development and that was when I was introduced to the thermal spray world and community. After my Ph.D., I started an academic career at the University of Ottawa and decided to push the link between materials and mechanical engineering further by working on the cold spray process, which was at the time more of an engineering/science curiosity than a real spray/coating process. I have been working on the development and use of this process ever since, combining both mechanical engineering and materials for interesting applications. Vistasp Karbhari: My career in academia has been at the interstices of structures, mechanics, and materials, building on the disciplines of mechanical and aerospace engineering, civil engineering, and materials. This has enabled me to conduct cutting-edge research in the areas of composite materials from the nano level to the structure, on the durability of materials and structures, and in terms of structural design, rehabilitation, and multi-threat mitigation. The ability to combine knowledge from the different disciplines allowed me to study effects during the processing of polymers and composites and to develop methods for handling large structural components using ambient and moderate temperature non-autoclave cure processes. This background also enables me to teach courses at the undergraduate and graduate levels linking materials details at the nano and constituent level (i.e., fiber, matrix, filler) with structural response and design. The ability to integrate the disciplines enables innovation across levels with a true understanding of how materials selection and processing affects design and structural responses. Marina Ruggles-Wrenn: My education (B.S. in mechanical engineering, M.S. in mechanics, and Ph.D. in mechanical engineering) focused primarily on mechanical engineering with little emphasis on materials science. During the early years of my professional career, I concentrated on experimental investigation and constitutive modeling of the inelastic deformation behavior of engineering alloys and on high-temperature structural design methods. My first significant (and exciting!) excursion into materials science occurred when I investigated effects of prior aging on rate sensitivity and cyclic hardening of a nuclear-grade stainless steel as part of my Ph.D. research. Thorough understanding of the microstructural nature of aging through the formation of precipitates was critical to selecting proper pretest heat treatments. Microstructural investigation of the samples with an SEM and a TEM was critical to determining that the precipitation heat treatments indeed produced the desired degrees of aging. Then some 20 years ago, my growing interest in the mechanical behavior and environmental durability of advanced ceramic matrix composites necessitated an aggressive study of the material microstructure and physical methods of materials characterization. Judith A. Todd: I completed my B.S. and Ph.D. degrees in materials science at Cambridge University with a strong emphasis on metallurgy and mechanical behavior. I then accepted a postdoctoral position at Imperial College of Science and Technology, London, to conduct research on the mechanical behavior of materials, advanced fracture mechanics, and fatigue. In this collaborative program between the materials science and engineering and mechanical engineering departments, I worked on the early development of the parameter C* (creep equivalent of the J contour integral) to predict creep crack growth in Cr-Mo steels (power plant steam pipe), and in aluminum alloy RR-58, (skin of Concorde). This began my life-long engagement with mechanical engineers. Except for my position as Department Head of Engineering Science and Mechanics at Penn State, I have held courtesy faculty positions in mechanical engineering departments throughout my academic career. What have you learned from a knowledge of mechanical engineering that helps in your materials career? Ruggles-Wrenn: My background in mechanical engineering has taught me to see the difference between the design of the material (typically a purview of materials scientists) and the design with the material (typically a purview of mechanical engineers). Both are extremely important. The best results are achieved through collaboration, when the design of the material goes hand-in-hand with the design with the
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