1305 Kinnear Rd
Columbus, OH 43212
Matt is a member of Michael Mills' group. He is currently studying the mechanisms of deformation in NiTi-based shape memory alloys. These materials are unique because of their ability to undergo large reversible strains and retain a "memory" of their original shape via a mechanically or thermally induced martensitic phase transformation. Despite their promise for use in surgical stents, solid state actuation, and even MEMS applications, they suffer from rapid functional fatigue during cycling. In an effort to better understand the responsible mechanisms and create more fatigue-resistant alloys, this work couples micropillar compression testing with post mortem scanning transmission electron microscopy (STEM) analysis of the resulting defect content. This enables the direct observation of dislocations associated with elementary transformation processes and has proven to be a novel method for studying the relationship between transformation and plasticity. These experimental results are compared with various modeling efforts to more clearly understand the mechanisms of defect generation in NiTi and other shape memory alloys.