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The microstructural changes and mechanical response of an HT-9 sample shock loaded to a peak pressure of 11 GPa have been investigated by TEM, XRD, microhardness and EBSD techniques. Dislocation densities obtained by both direct measurements (via TEM) and indirect calculations (by XRD and hardness) indicate that shock loading results in ~2-3 fold increase in dislocation density. TEM analyses show that the shape, and density of the dislocations change after shock loading. In addition, shock loading causes local plastic deformation of the continuous parallel lath structure in some regions, together with an overall decrease in the aspect ratio of laths due to local plastic deformation and lath fragmentation. As a result of XRD analyses, the fraction of edge dislocations is determined to increase by ~24% after shock loading. Furthermore, hardness increases by ~40 HV after shock loading due to the increased dislocation density. EBSD analyses show that the fraction of CSL boundaries decreases by ~5-10 % as a result of shock loading.

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Actively cooled thermostructural panels for use in emerging hypersonic flight systems require advanced materials able to support substantial loads at elevated temperatures. Identifying formable structural materials with strength, toughness, and oxidation resistance is a major challenge in this advancing technology. Geometrical optimization of thermostructural panels for scramjet applications minimizing mass with appropriate mechanical strength and cooling capacity combinations often requires submillimeter wall and face-sheet thicknesses. A new processing method was developed, resulting in rectangular-channeled panels made of nickel-based precipitation-strengthened alloy in a previously unobtainable thin-walled geometry suitable for active cooling. The processing method begins with panel fabrication from submillimeter-thin sheets of a Ni-based solid-solution alloy. The strength of the panel is subsequently increased by vapor phase aluminization combined with an annealing treatment. The vapor phase strengthening process increases the yield strength of the panel by a factor of approximately three. Panels were fabricated with geometry representative of optimal designs and tested at high temperature with active cooling in both as-fabricated and strengthened states. The strengthened, actively cooled panel withstood a temperature 478 C higher than the as-fabricated panel before failure under high heat flux conditions, indicating that the vapor phase strengthening process provides substantial new performance capabilities.