Accession Number : AD0763706

Title :   The Effect of Thermal Cycling on the Structure of the Co-Co3Cb Eutectic.

Descriptive Note : Technical rept.,

Corporate Author : AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Arnson,H. L.

Report Date : DEC 1972

Pagination or Media Count : 151

Abstract : Unidirectionally solidified Co-Co3Cb eutectic samples with and without a minor addition nickel were subjected to long time annealing and thermal cycling treatments. The eutectic showed metallographic and crystallographic stability after vacuum annealing for periods up to 1000 hours at 1000C. Structural stability was also observed during thermal cycling experiments conducted completely above the temperature of the cobalt FCC to HCP, HCP to FCC phase transformation. However, when the thermal cycle included the cobalt transformation temperature, samples containing 0.2 weight per cent nickel showed microstructural breakdown, whereas samples with 0.01 weight per cent nickel did not. In addition, the latter samples quickly developed and retained the FCC form of cobalt during cycling. (Modified author abstract)

Descriptors :   (*COBALT ALLOYS, EUTECTICS), NIOBIUM ALLOYS, INTERMETALLIC COMPOUNDS, FREEZING, STABILITY, THERMAL STABILITY, FIBER METALLURGY, MICROSTRUCTURE, PHASE STUDIES, ELECTRON MICROSCOPY, GAS TURBINES, THESES

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE