Deformation and Fracture of Ruthenium Aluminide

Purdue Research Foundation, West Lafayette IN

Investigators

Abstract

0076219 Johnson Good room temperature toughness has been reported based on limited, qualitative tests on ruthenium aluminide, RuAl. This is unusual for intermetallic alloys that have the CsCl (B2) type crystal structure. Previous experiments suggest that this unusual toughness originates from the multiplicity of slip along the <110> and <100> directions which differs considerably from that of most other B2 compounds in which the common slip directions are either <111> or <100>. Reasons, however, for this unusual deformation behavior have not yet been identified, probably due to the difficulty in processing single crystals and the exotic nature of the alloy. This research effort directly measures the deformation behavior and fracture toughness of RuAl using single crystals and multiphase composite microstructures of controlled orientations. Preliminary work has shown that appropriate materials for testing can be produced by cold crucible Czochralski techniques. The primary goal for the research is to explain the deformation behavior of RuAl and to correlate the similarities and differences with that of other B2 compounds. With this knowledge, the underlying mechanisms for deformation and fracture can be identified and modeled which will lead to design strategies for improving the toughness of semi-brittle materials. %%% Intermetallics are often considered candidate materials for high temperature structural applications due to the high melting temperature and good oxidation resistance of many intermetallic compounds. However, problems with brittleness have not been solved for intermetallic alloy systems that are to operate above the use temperature of the superalloys. ***