Strengthening of NiAl matirix composites (Annual report October 1, 1994-November 30, 1995)

Technical Report · Thu Nov 30 04:00:00 EST 1995

OSTI ID:236857

Arsenault, R J

A detailed mechanism has been developed which will predict the formation of vacancy-producing jogged-screw dislocations. The motion of these screw dislocations is the thermally-activated rate-controlling mechanism for both the matrix and the NiAl matrix composites. With the exception of very small subgrain or grain sizes and Al2O3 particle size (0.5 micrometer), the internal stress is independent of stress and temperature. The increase in the internal stress caused by the reinforcement is the strengthening mechanism. The apparent unusual result of an increase in dislocation density due to relaxation of the thermal residual stress as the particle size increases in Al2O3/NiAl composites has been explained by a new model. This model, which employs FEM and crystal plasticity, is based on the low symmetry of the NiAl B2 crystal structure which results in a paucity of independent slip systems.

• Research Organization: Maryland Univ., College Park, MD (United States)
• OSTI ID: 236857
• Report Number(s): AD-A--302545/9/XAB; MML--1-1994; CNN: Contract N00014-94-1-0118
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ADDITIONS
COMPOSITE MATERIALS
CRYSTAL STRUCTURE
MATERIALS WORKING
MATRIX MATERIALS
NICKEL BASE ALLOYS
SCREW DISLOCATIONS
STRENGTH FUNCTIONS
TEMPERATURE DEPENDENCE