Publications

19 Results
Skip to search filters

Thermal conductivity measurements and modeling of ceramic fiber insulation materials

International Journal of Heat and Mass Transfer

Headley, Alexander H.; Hileman, Michael B.; Robbins, Aron R.; Piekos, Edward S.; Stirrup, Emily K.; Roberts, Christine C.

Ceramic fiber insulation materials are used in numerous applications (e.g. aerospace, fire protection, and military) for their stability and performance in extreme environments. However, the thermal properties of these materials have not been thoroughly characterized for many of the conditions that they will be exposed to, such as high temperatures, pressures, and alternate gaseous atmospheres. The resulting uncertainty in the material properties can complicate the design of systems using these materials. In this study, the thermal conductivity of two ceramic fiber insulations, Fiberfrax T-30LR laminate and 970-H paper, was measured as a function of atmospheric temperature and compression in an air environment using the transient plane source technique. Furthermore, a model is introduced to account for changes in thermal conductivity with temperature, compression, and ambient gas. The model was tuned to the collected experimental data and results are compared. The tuned model is also compared to published data sets taken in argon, helium, and hydrogen environments and agreement is discussed.

More Details
TYPE Journal Article YEAR 2019
ScopusOSTIDOI

Effects of spatial energy distribution on defects and fracture of LPBF 316L stainless steel

Solid Freeform Fabrication 2019: Proceedings of the 30th Annual International Solid Freeform Fabrication Symposium - An Additive Manufacturing Conference, SFF 2019

Jost, Elliott W.; Miers, John C.; Robbins, Aron R.; Moore, David G.; Saldana, Christopher

Measures of energy input and spatial energy distribution during laser powder bed fusion additive manufacturing have significant implications for the build quality of parts, specifically relating to formation of internal defects during processing. In this study, scanning electron microscopy was leveraged to investigate the effects of these distributions on the mechanical performance of parts manufactured using laser powder bed fusion as seen through the fracture surfaces resulting from uniaxial tensile testing. Variation in spatial energy density is shown to manifest in differences in defect morphology and mechanical properties. Computed tomography and scanning electron microscopy inspections revealed significant evidence of porosity acting as failure mechanisms in printed parts. These results establish an improved understanding of the effects of spatial energy distributions in laser powder bed fusion on mechanical performance.

More Details
TYPE Conference Poster YEAR 2019
ScopusOSTI
19 Results
19 Results