Search NASA⌕ Search

Engineering topics

Wilcox, R. C.

Publications and source records attributed to Wilcox, R. C..

4 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Chemical compatibility of cartridge materials

The objectives were to determine the chemical compatibility of titanium-zirconium-molybdenum (TZM) with GaAs and CdZnTe, and Inconel with HgCdTe and HgZnTe. At the present time, no other studies regarding the compatibility of these crystal components and their respective cartridge materials have been performed. This study was to identify any possible problems between these materials to insure proper containment of possibly hazardous fumes during crystal growth experiments. In this study, the reaction zone between the materials was studied and the amount of degradation to the system was measured. Detailed results are presented.

Ambrose, Bryan↗
NASA NTRS1991

Fracture of single crystals of the nickel-base superalloy PWA 1480E in hydrogen at 22 C

The present study investigates the hydrogen-induced fracture behavior of notched single crystals of the PWA 1480E nickel-based superalloy. Notched single crystals with seven different crystal orientations were tensile tested at 22 C in a hydrogen atmosphere at 34 MPa. Hydrogen-enhanced cleavage along 100-line planes in the notched region was found to be due to cracking along the gamma/gamma-prime interfaces. Cleavage on 111-line-type planes was observed only outside the notch region. The occurrence of 100- and 111-line-types of cleavage was independent of the single-crystal orientation. Outside the notch region, the fracture surfaces of specimens tested in hydrogen appeared very similar to those tested in helium. Differences in the fracture surfaces were located primarily near the notch region.

Chen, P. S.↗
NASA NTRS1991

Fracture of single crystals of the nickel-base superalloy PWA 1480E in helium at 22 C

The fracture behavior and deformation of He-charged (at 22 C) single crystals of PWA 1480E Ni-base superalloy were investigated using SEM and TEM techniques to observe the behavior of tensile fractures in notched single crystals with seven different crystal growth orientations: 100-line, 110-line, 111-line, 013-line, 112-line, 123-line, and 223-line. To identify the cleavage plane orientation, a stereoscopic technique, combined with the use of planar gamma-prime morphologies, was applied. It was found that gamma-prime particles were orderly and closely aligned with edges along the 100-line, 010-line, and 001-line-oriented directions of the gamma matrix. Different crystal growth orientations were found not to affect the morphology of gamma-prime particles. The accumulation of dislocations around gamma/gamma-prime interfaces formed strong barriers to subsequent dislocation movement and was the primary strengthening mechanism at room temperature.

Chen, P. S.↗