Statistical Prediction of Static Fatigue Lifetime in Ceramic and Glass
Abstract not provided.
Publications
R-Curve Measurements of silicon nitride glass ceramic and PZT
Abstract not provided.
Photoluminescence Spectroscopy to Determine Residual Stresses in Glass-to-Metal Seals
Abstract not provided.
Photoluminescence Spectroscopy to Determine Residual Stresses in Glass-to-Metal Seals
In components with two materials, such as glass-to-metal (GtM) seals, residual stress can reduce long-term reliability. Therefore, it is important to be able to accurately measure residual stress within these components. The residual stress can be from a large strain due to the mismatch of thermo-physical response of the two materials or a small strain due to stress and/or structural relaxation. Both modeling and experimental measurements were conducted on multiple GtM seals constructed with CGI 930 glass with purposely added alumina particles. The alumina particles have an established Cr fluorescence pattern and the shift in position of these peaks can accurately measure the strain of the alumina crystals. Photoluminescence spectroscopy (PLS) technique was utilized due to its non-destructive nature and high spatial resolution. PLS scans of these components were analyzed and compared to the models developed previously.
Stress Mapping Glass-to-Metal Seals using Photoluminescence Spectroscopy
Abstract not provided.
Determination of Interfacial Properties in Glass to Metal seals using Pin Push-out Test
Abstract not provided.
Wetting Behavior of Glass-Ceramic on Stainless Steel
Abstract not provided.
Stress Mapping in Glass-to-Metal Seals using Indentation Crack Lengths
Abstract not provided.
Stress Mapping in Glass-to-Metal Seals using Indentation Crack Lengths
Predicting the residual stress which develops during fabrication of a glass-to-metal compression seal requires material models that can accurately predict the effects of processing on the sealing glass. Validation of the predictions requires measurements on representative test geometries to accurately capture the interaction between the seal materials during a processing cycle required to form the seal, which consists of a temperature excursion through the glass transition temperature of the sealing glass. To this end, a concentric seal test geometry, referred to as a short cylinder seal, consisting of a stainless steel shell enveloping a commercial sealing glass disk has been designed, fabricated, and characterized as a model validation test geometry. To obtain data to test/validate finite element (FE) stress model predictions of this geometry, spatially-resolved residual stress was calculated from the measured lengths of the cracks emanating from radially positioned Vickers indents in the glass disk portion of the seal. The indentation crack length method is described, and the spatially-resolved residual stress determined experimentally are compared to FE stress predictions made using a nonlinear viscoelastic material model adapted to inorganic sealing glasses and an updated rate dependent material model for 304L stainless steel. The measurement method is a first to achieve a degree of success for measuring spatially resolved residual stress in a glass-bearing geometry and a favorable comparison between measurements and simulation was observed.
Microstructural Effects on Glass-Ceramic Mechnaical Response and Slow Crack Growth Behavior
Abstract not provided.
Stress Mapping in Glass-to-Metal Seals using Indentation Crack Length Measurements
Abstract not provided.
11 Results