William L. Johnson
California Institute of Technology
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Primary Section: 31, Engineering Sciences Secondary Section: 33, Applied Physical Sciences Membership Type:
Member
(elected 2007)
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Research Interests
Professor Johnson does research on non-equilibrium and metastable materials including undercooled liquids, metallic glasses, and non-equilibrium crystals. His early work involved characterizing the thermodynamic stability of crystals with respect to melting and solid state "crystal to glass" transformations (see W.L. Johnson, Prog. in Mat. Sci., 1986). In the early 1990's, his group developed novel families of metallic alloys which form bulk metallic glasses, or BMG's (Peker and Johnson, Appl. Phys. Lett., 1993) Later work on these glass forming liquids has covered studies thermodynamics, rheology and flow, relaxation dynamics, and the glass transition in metallic glasses (e.g. see W.L. Johnson, Mat. Res. Soc. Bull., 1999). Over the past decade, his group has investigated the thermal, physical, and mechanical properties of solid metallic glasses (for example, Johnson and Samwer, Phys. Rev. Lett., 2005) and metallic glass matrix composites. The research on metallic glasses has focused on deformation, plastic flow, shear banding, and fracture of glasses. Work on glassy matrix composites has led to development of "structural amorphous metals" with exceptional combinations of strength, ductility, and toughness (e.g. Hays, Kim, and Johnson, Phys. Rev. Lett., 2000). Prof. Johnson has been actively involved in technology transfer and engineering applications of metallic glasses. He co-founded a company, Liquidmetal Technologies Inc., focused on the commercialization of metallic glass technology.
