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Our goal is to develop and demonstrate a MEMS-based methodology for evaluating time-dependent mechanical properties of materials that undergo exposure to extreme and harsh environments (e.g., temperature extremes, high radiation, corrosive chemistries, etc.). Such test methods hold promise for providing a high throughput route to thoroughly measuring the remaining lifetime of highly irradiated materials present in today’s nuclear power plants, as well as the suitability of new alloys for next generation nuclear plants.
Classically, measurement of the mechanical properties and reliability of bulk-scale materials is performed with macroscopic specimens and methods. Specimen preparation limitations, miniaturized load-frame tooling problems, and inadequate understanding of the roles of specimen size and constraint on properties have hindered the use of micrometer-scale specimens and techniques. We are developing a new approach that combines specimen preparation techniques such as focused ion beam (FIB) milling with microtechnology-based test tools. This will enable evaluation of large populations of specimens, on-chip, and in parallel, to provide statistically significant results. Properties of small-scale structures are linked to those of bulk-scale structures through application of three-dimensional, imaged-based finite element modeling. Currently, we use FIB to obtain micrometer-scale specimens from structural materials irradiated in test reactors, accelerators, or working power reactors for insertion into prefabricated on-chip test structures. Ultimately, we will fabricate arrays of test structures with on-chip control, actuation, and sensing. This will provide long-term, in situ testing of time-dependent mechanical properties of materials to be used in NGNP and fusion reactors.
Mask Layout for "Drop-In" Microsystem Tensile Structure.
Start Date:October 1, 2008
Lead Organizational Unit:mml
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