Search NASA⌕ Search

Engineering topics

Maloy, Stuart A

Publications and source records attributed to Maloy, Stuart A.

10 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2012

Overview of DOE-NE Structural Materials Research, Materials Challenges and Operating Conditions

This presentation summarized materials conditions for application of nanomaterials to reactor components. Material performance is essential to reactor performance, economics, and safety. A modern reactor design utilizes many different materials and material systems to achieve safe and reliable performance. Material performance in these harsh environments is very complex and many different forms of degradation may occur (often together in synergistic fashions). New materials science techniques may also help understand degradation modes and develop new manufacturing and fabrication techniques.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Impact properties of irradiated HT9 from the fuel duct of FFTF

This paper reports Charpy impact test data for the ACO-3 duct material (HT9) from the Fast Flux Test Facility (FFTF) and its archive material. Irradiation doses for the specimens were in the range of 3– 148 dpa and irradiation temperatures in the range of 378–504 *C. The impact tests were performed for the small V-notched Charpy specimens with dimensions of 3 * 4 * 27 mm at an impact speed of 3.2 m/s in a 25 J capacity machine. Irradiation lowered the upper-shelf energy (USE) and increased the transition temperatures significantly. The shift of ductile–brittle transition temperatures (DDBTT) was greater after relatively low temperature irradiation. The USE values were in the range of 5.5–6.7 J before irradiation and decreased to the range of 2–5 J after irradiation. Lower USEs were measured for lower irradiation temperatures and specimens with T-L orientation. The dose dependences of transition temperature and USE were not significant because of the radiation effect on impact behavior nearly saturated at the lowest dose of about 3 dpa. A comparison showed that the lateral expansion of specimens showed a linear correlation with absorbed impact energy, but with large scatter in the results. Size effect was also discussed to clarify the differences in the impact property data from subsize and standard specimens as well as to provide a basis for comparison of data from different specimens. The USE and DDBTT data from different studies were compared.

Byun, Thak Sang↗
DOE OSTI2011

Relative Defect Density Measurements of Laser Shock Peened 316L Stainless Steel Using Positron Annihilation Spectroscopy

The surface of an annealed 316L stainless steel coupon was laser shock peened and Vickers hardness measurements were subsequently taken of its surface. This Vickers hardness data was compared with measurements taken using the technique of positron annihilation Doppler broadening spectroscopy. When compared, a correlation was found between the Vickers hardness data measurements and those made using Doppler broadening spectroscopy. Although materials with a high defect density can cause the S-parameter measurements to saturate, variations in the Sparameter measurements suggest that through further research the Doppler broadening technique could be used as a viable alternative to measuring a material's hardness. In turn, this technique, could be useful in industrial settings where surface hardness and surface defects are used to predict lifetime of components.

36 MATERIALS SCIENCE↗