PNNL

Abstract

The use of SiC composites in fusion environments likely requires joining of plates using reactive joining or brazing. One promising reactive joining method uses solid-state displacement reactions between Si and TiC to produce Ti3SiC2 + SiC. We continue to explore the processing envelope for this joint for the TITAN collaboration in order to produce optimal joints to undergo irradiation studies in HFIR. The TITAN collaboration has designed miniature torsion joints for preparation, testing, and irradiation in HFIR. PNNL synthesized 40 miniature torsion joints and several were tested for shear strength prior to irradiation testing in HFIR. The resulting tests indicated that 1) joint fixture alignment problems cause joint strengths to be lower than optimal, 2) that non-planar torsion test failures limit the effectiveness of the miniature specimen design, and 3) that several joints that were well aligned had high shear strengths and promising mechanical properties. In summary, we now show conclusively that high joint strengths cause non-planar shear fracture and complicate strength analysis for miniature torsion specimens.