Accession Number : AD0820669

Title :   INVESTIGATION OF THE BASIC PARAMETERS AFFECTING THE PROPERTIES OF INTERMETALLIC COMPOUNDS. PART VIII.

Descriptive Note : Final summary rept. 11 Feb 66-31 Mar 67,

Corporate Author : GENERAL ELECTRIC CO SCHENECTADY NY RESEARCH AND DEVELOPMENT CENTER

Personal Author(s) : Cline, Harvey E.

Report Date : AUG 1967

Pagination or Media Count : 31

Abstract : Mechanical properties of the eutectic between CoAl and Co were measured over a range of temperatures and strain rates for a variety of microstructures produced by directional solidification, by thermomechanical processing, and by powder processing. Directional solidification led to rod-like, lamellar, and irregular microstructures. The hot worked structure consisted of fibers of CoAl in a cobalt-rich matrix. At room temperature the strength of the wrought material increased with decreasing grain size, while at 1000 C the larger grain sized material was stronger. AT HIGH TEMPERATURES THE DIRECTIONALLY SOLIDIFIED MATERIAL WAS STRONGER and less strain rate sensitive than the hot-rolled material. The fine grained hot worked material became superplastic at high temperatures, with tensile elongations greater than 850%, while at room temperature this material was ductile and impact resistant because of the ductile matrix. Fracture occurred in the directionally solidified material at elevated temperatures by interphase separation and at room temperature by cracks in the intermetallic phase. The CoAl-Co eutectic was found to have a stable microstructure at elevated temperatures. It was found that the CoAl intermetallic remains ordered at elevated temperatures. (Author)

Descriptors :   *ALUMINUM ALLOYS), (*INTERMETALLIC COMPOUNDS, SCIENTIFIC RESEARCH), (*COBALT ALLOYS, STABILITY, EUTECTICS, MICROSTRUCTURE, FIBERS, FRACTURE(MECHANICS), TENSILE PROPERTIES, TEST METHODS, IMPACT TESTS, HIGH TEMPERATURE, THICKNESS, MELTING POINT, SOLUBILITY, HARDNESS, POWDER METALS, EXTRUSION, DUCTILITY, ELONGATION, CORROSION RESISTANCE, HOT WORKING, ANNEALING.

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE