SBIR-STTR Award

We propose using laser chemical vapor deposition (LCVD) to improve the materials used in hypersonic systems. We see several ways our process can improve materials for this challenging environment. For phase 1 we will perform detailed customer interviews with end users at the Air Force to find the most urgent need(s) for which our system can add value in addition to a technical demonstration. One problem we hope to help solve is in forming stronger connections between mismatched materials. There are significant stresses in supersonic vehicles because of thermal variations. Joints of different materials with different coefficients of thermal expansion have increasing stress as temperatures increase. Often this stress leads to the joint breaking apart and the device failing. Contrary to a weld or a joint, a material with a slowly changing composition can distribute the thermal stresses over a larger volume and avoid failure. However, fabricating materials that slowly grade from one material to another is not possible with many fabrication techniques. We will use LCVD to grow a fiber with varying composition.

We propose a thermally resistive aperture design for hypersonics applications. Apertures made from SiN are not thermally matched to the carbon carbon casing that surrounds the aperture. This thermal mismatch leads to cracks and device failure. We propose connecting the aperture and the casing with microscopic fibers that distribute the stress from thermal strains throughout the fiber length. Since the stress is distributed the aperture and casing will be stronger and more resilient to thermal changes.