Deformation and Fracture of Advanced Anisotropic Superalloys.
Abstract
The modern single crystal superalloy baseline of Ni-5A1-2Ti-1Nb-9Cr-12W (by weight) was selected (PWA 1444). The Re/W ratio was varied from 0.0 to 1.0 as the Re + W was held constant at 12 wt %. Single crystals were grown with axial orientations of <001>, <110>, and <111> from four different alloys and were fully heat treated (gamma prime solution + age). An additional alloy was made at 4Ta/4W/4Re in the three high symmetry orientations. Test specimens of the compressive and tensile creep/rupture design were obtained by sectioning or electrochemical machining. Creep data were obtained in tension and compression with temperature/stress combinations of 816 C/650 Mpa, 899 C/380 MPa, 982 C/220 MPa and 1066 C/138 MPa (1500 F/94 ksi, 1650 F/55 ksi, 1800 F/32 ksi and 1950 F/20 ksi). Crystals were characterized by chemical analysis, optical metallography and crystallographic orientation determination by the Laue method. Aging studies were carried out at 816 C (1500 F), 899 C (1650 F), 982 C (1800 F) and 1066 C (1950 F). The Re content was found to systematically and substantially refine the gamma prime particle size. Transmission electron microscopy was carried out after 0.20% creep strain at 899 C (1650 F). The primary slip system was consistently (111) <110> for <001> and <110> oriented specimens but (100) <110> slip was found for the <111> oriented tensile and compressive samples at 0% Re. Higher Re levels showed a lesser tendency for cube slip. The Re addition substantially strengthens all three orientation tested, particularly <111>.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1979
- Accession Number
- ADA080088
Entities
People
- Anthony F. Giamei
Organizations
- Pratt & Whitney