THE SYSTEM TITANIUM-ZIRCONIUM-OXYGEN. Final Report from November 1, 1956 to August 31, 1959

Technical Report · Mon Jul 13 04:00:00 EDT 1959

OSTI ID:4130041

Hoch, M; Dean, R L; Hwu, C K; Wolosin, S M

The general shape of the 1450 deg C isotherm of the Ti-TiO--ZrO/sub 2/-- Zr region was calculated from the surrounding binary phase diagrams. The phase boundaries were determined. At 1450 deg C the system showed a large body- centered cubic beta field, which extends from the two metal-oxygen binary systems as a Gaussian error function, and is stable up to 30 at.% oxygen when titanium and zirconium are present in equal amounte. At higher oxygen concentrations, the beta field was in equilibrium with tetragonal ZrO/sub 2/. The following four regions, with three solid phases, were found present: two hexagonal alpha + beta + tetragonal ZrO/sub 2/, alpha + TiO + tetragonal ZrO/sub 2/, and TiO + tetragonal ZrO/sub 2/ + cubic ZrO/sub 2/. On cooling, the beta phase transformed into the alpha phase, going through the omega transition phase. The isotherm at 1500 deg C for the region TiO--TiO/sub 2/--ZrO/sub 2/ was obtained using x-ray diffraction. At 1500 deg C a large cubic ZrO/sub 2/ region was present, which deformed into the ortho rhombic TiZrO/sub 4/ when the composition was close to the TiO/sub 2/--ZrO/sub 2/ binary. A very large two-phase field, TiO + cubic ZrO/ sub 2/, was present. The following regions, with three solid phases in equilibrium, were found: TiO + Ti/sub 2/O/sub 3/ + cubic ZrO/sub 2/, Ti/sub 2/O/ sub 3/ + Ti/sub 3/O/sub 5/ + cubic ZrO/sub 2/, Ti/sub 3/O/sub 5/ i TiO/sub 2/ + cubic ZrO/sub 2/ (TiZrO/sub 4/). These regions were relatively small. The activities of titanium and TiO in the alpha + TiO + tetragonal ZrO/sub 2/ and the two alpha + beta + tetragonal ZrO/sub 2/ regions were measured using the Kaudsen effusion method. In the alpha + TiO + tetragonal ZrO/sub 2/ region the activities of both titanium and TiO were the same, as in the Ti + TiO binary. In the two alpha + beta + tetragonal ZrO/sub 2/ regions, the titanium activity was high, and the TiO activity very low, though all phases present contained at least 30 at.% oxygen. This indicated a short-range order in the solid phases, zirconium atoms being preferentially surrounded by oxygen. The solidus and liquidus surfaces were determined by observing samples suspended with a fine tungsten wire in a tungsten crucible, and heated in vacuum. Eighty-nine compositions were investigated: eight univarient points, seven ternary eutectic points, and one congruent melting point were found. Cubic ZrO/sub 2/ decomposed through a peritectic reaction into liquid + tetragonal ZrO/sub 2/. The oxidation of titanium-zirconium alloys was investigated. The presence of zirconium in titaniuma, and vice versa, decreased the oxidation resistance, and the alloys oxidized faster than the pure metals. (C.J.G.)

• Research Organization: Cincinnati. Univ.
• NSA Number: NSA-15-000638
• OSTI ID: 4130041
• Report Number(s): WADC-TR-59-539; AD-232887
• Country of Publication: United States
• Language: English

Related Subjects

ATOMIC MODELS
CONFIGURATION
COOLING
CRUCIBLES
DIFFRACTION
EUTECTICS
GAUSS FUNCTION
GRAIN BOUNDARIES
HEATING
HIGH TEMPERATURE
INTERMETALLIC COMPOUNDS
KNUDSEN EFFUSION
LIQUIDS
MEASURED VALUES
MELTING POINTS
METALS, CERAMICS, AND OTHER MATERIALS
OXIDATION
OXYGEN
PHASE DIAGRAMS
QUANTITATIVE ANALYSIS
QUANTITY RATIO
REACTION KINETICS
SOLID SOLUTIONS
SOLIDS
STABILITY
SURFACES
TITANIUM ALLOYS
TITANIUM OXIDES
TUNGSTEN
VACUUM
WIRES
X RADIATION
ZIRCONIUM ALLOYS
ZIRCONIUM OXIDES