A critical national need exists for radically improved machinable glass ceramic-to-metal joints for nuclear and other applications. At present, such joints are not available on a reliable, cost-effective basis. Furthermore, they are not always strong, reproducibly vacuum-tight, nor sufficiently thermal shock resistant. In Phase I, the technical merit and feasibility of our proposed approaches to solving these problems will be studied by (1) minimizing unwanted elemental segregations resulting from gravity to achieve generally strong and improved joints, (2) examining the critical transient thermal stress profiles over the joint regions, and (3) specially grading the elemental compositions inside the joint regions to compensate for the mismatch stress profiles for minimizing mechanical failures. Corresponding tasks will be to develop methods to minimize the gravitational segregation effects, to determine the critical transient mismatch profiles, and to study ways for designing specially tailored graded seals.Anticipated Results/Potential Commercial Applications as described by the awardee:The results of this study could revolutionize future machine designs in many fields. A new generation of reliable but low-cost glass ceramic-to-metal joints having much improved performances could lead to widespread applications in lighter, stiffer, more temperature- or thermal shock-resistant and otherwise vastly improved nuclear or fusion reactors, automobile engines, industrial machineries, airplanes, helicopters, satellites, missiles, advanced defense systems, precision parts and components, buildings or structures, sporting or recreation equipment, and medical or electronic and electrical parts/instruments and other commercial products.
