Micro-characterization of corrosion resistant zirconium-based alloys

Book · Sat Dec 31 04:00:00 EST 1994

OSTI ID:55665

Isobe, Takeshi; Matsuo, Yutaka; Mae, Yoshiharu ^[1]

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1. Mitsubishi Materials Corp., Saitama (Japan). Central Research Inst.

On the basis of experimental results using button ingots, three zirconium, tin, niobium, iron, and chromium (Zr-Sn-Nb-Fe-Cr) alloy compositions (VAZ series) with superior corrosion resistance and equivalent mechanical properties to those of conventional Zircaloy-4 were determined in a previous work. The alloys of these compositions were vacuum arc melted in 5-kg ingots and were fabricated into sheets with various annealing parameters. They were subjected to long-term corrosion tests in water at 633 K and tension tests at room and elevated (658 K) temperatures. Results showed that the corrosion weight gains and the hydrogen uptakes of VAZ alloys were about 50% and 20 to 60% of that of Zircaloy-4, respectively, and that the tensile strengths were equivalent to those of Zircaloy-4. Transmission electron microscopy/energy dispersive X-ray (TEM/EDX) analysis showed that niobium precipitated in VAZ alloys containing only 0.2% by weight niobium. In order to clarify the effects of niobium at low concentration on the corrosion property, zirconium-tin-niobium (Zr-Sn-Nb) alloys (iron/chromium precipitate-free) were prepared from a zirconium X-bar and subjected to corrosion test in 633 K water. Results showed that the corrosion resistance remarkably increased with increasing niobium content from zero up to 300 ppm and was approaching the level of VAZ alloys. It is thought that a very small amount of niobium, almost dissolved in the matrix, leads to the superior corrosion resistance of VAZ alloys in pure water.

• OSTI ID: 55665
• Report Number(s): CONF-930611--; ISBN 0-8031-2011-7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CHROMIUM ALLOYS
COMPARATIVE EVALUATIONS
CORROSION RESISTANCE
EXPERIMENTAL DATA
HYDRIDATION
INTERMETALLIC COMPOUNDS
IRON ALLOYS
METALLURGICAL EFFECTS
MICROSTRUCTURE
NIOBIUM
NIOBIUM ALLOYS
REACTOR MATERIALS
TENSILE PROPERTIES
TIN ALLOYS
ZIRCONIUM BASE ALLOYS