Phase transformations in the titanium-niobium binary alloy system

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5429759

Moffat, D L

A fundamental study of the phase transformations in the Ti-Nb binary alloy system was completed. Eight alloys in the range 20 to 70 at% Nb were investigated using transmission electron microscopy, light metallography, and x-ray diffraction. Measurements of electric resistivity and Vicker's microhardness also were performed. Emphasis was placed on the minimization of interstitial contamination in all steps of alloy fabrication and specimen preparation. In order to eliminate the effects of prior cold working, the alloys studied were recrystallized at 1000/sup 0/C. Phase transformations were studied in alloys quenched to room temperature after recrystallization and then isothermally aged, and in those isothermally aged without a prior room temperature quench. It was found that the microstructures of the quenched 20 and 25% Nb alloys were extremely sensitive to quench rate - with a fast quench producing martensite, a slow quench, the omega phase. Microstructures of the higher niobium content alloys were much less sensitive to quench rate. The microstructures of the isothermally aged 20 and 25% Nb alloys were found to be sensitive to prior thermal history. Alloys quenched to room temperature and then aged at 400/sup 0/C contained large omega precipitates, while those aged without an intermediate room temperature quench contained alpha precipitates.

• Research Organization: Wisconsin Univ., Madison (USA)
• OSTI ID: 5429759
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOY SYSTEMS
ALLOYS
BINARY ALLOY SYSTEMS
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
HARDNESS
HEAT TREATMENTS
HIGH TEMPERATURE
MECHANICAL PROPERTIES
MICROHARDNESS
MICROSTRUCTURE
NIOBIUM ALLOYS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
TITANIUM ALLOYS
VERY HIGH TEMPERATURE