All-Conference Events: Friday All-conference
Program Organizers: Aaron Stebner, Colorado School of Mines
Friday 4:00 PM
July 14, 2017
Room: Crystal Ballroom B&C
Location: Hyatt Regency Chicago
Session Chair: Aaron Stebner, Colorado School of Mines
4:00 PM Keynote
Martensite Fundamentals as they Pertain to the Medical Device Industry: Tom Duerig1; 1Confluent Medical Technologies
After forty years of struggling, applications for NiTi shape memory alloys abruptly took off in the early 1990’s. The charge was led by medical applications, but we are now witnessing similar success in the field of actuation. Such explosive growth after a long stagnant period left much of the fundamental science behind. While the medical industry is not flying blind, there are areas in which a better scientific foundation is needed.Some of these needs, including: (a) the R-phase/Martensite competition and its significance to superelastic behavior, (b) complications in lifetime prediction caused largely by NiTi’s non-linear stress strain behavior and deformation asymmetry, (c) the practical impact of strain localization (Lüders deformation), (d) and the wide variations in observed elastic moduli will be reviewed in this presentation. The intent is to raise open questions more than to provide answers, with hope of stimulating research interests that support out industry’s engineering needs.
4:40 PM Keynote
Martensite in Carbon Steels: 40 Years of ICOMAT, 1976 to 2017 and Beyond: George Krauss1; 1Colorado School of Mines
Martensite in steels continues to be of vital importance for vast numbers of load-bearing applications, but it must be recognized that as-quenched martensite crystals are only one component of complex microstructural systems. Nevertheless supersaturated, fine lath or plate shaped martensitic crystals with their inherent dislocation substructure become the base for the many derivative microstructures produced by tempering. At low temperatures martensitic substructure dominates strengthening and at high temperatures the remnant martensite crystal size becomes the major strengthening component. The mechanisms and kinetics of dislocation recovery, the precipitation of transition carbides, retained austenite transformation, cementite formation, cementite enrichment, alloy carbide secondary hardening, martensite crystal growth and stabilization, all as a function of tempering, carbon content, and alloying, require more research to optimize composite structures and performance. Highly developed experimental techniques now available will help to characterize the nanostructure, substructure, and microstructures of martensitic physical systems in steel.
5:20 PM Concluding Comments