Structures of grain boundaries and aspects of deformation behavior in Ni3Al alloys. Final report, September 1983-August 1988

Technical Report · Mon Aug 01 04:00:00 EDT 1988

OSTI ID:7046578

Kerans, R J

The structures of two grain boundaries in Ni3Al were determined using transmission electron microscopy (TEM). The line directions and spacings of secondary grain boundary dislocation (gbds) were calculated for coincidence site lattice (CSL) relationships near the experimentally determined misorientations. The structures of the boundaries were found to be in good agreement with 9 and 31b relationships of the ordered lattice. The grain boundary dislocations were found to be characteristic of the ordered structure. No grouping of partial gbds was observed. Lattice dislocations consisting of pairs of 1/3 (112) superpartials bounding extended superlattice intrinsic stacking faults (SISFs) were observed by TEN. They were found to independently react to APB coupled 112 110 pairs in the commonly observed pure screw orientation. Implications with regard to Kear-Wilsdorf type locking mechanisms and deformation behavior are discussed. Boron was observed to have strong effects upon the population of boundary types, grain size, and grain growth. In addition, small amounts of B completely eliminate widely extended stacking faults. It is concluded that effects of B other than influencing boundary cohesion are important.

• Research Organization: Wright Lab., Wright-Patterson AFB, OH (United States)
• OSTI ID: 7046578
• Report Number(s): AD-A-276646/7/XAB; WL-TR--94-4011
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
BORON
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISLOCATIONS
DOCUMENT TYPES
ELEMENTS
GRAIN BOUNDARIES
GRAIN SIZE
LINE DEFECTS
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
PROGRESS REPORT
SEMIMETALS
SIZE
STACKING FAULTS