Anneal hardening and flow softening in beta zirconium--niobium alloys

Journal Article · Tue May 01 04:00:00 EDT 1979 · Metall. Trans., A; (United States)

DOI:https://doi.org/10.1007/BF02658325· OSTI ID:6298482

Jonas, J J ^[1]; Heritier, B; Luton, M J

---

1. McGill Unic., Montreal, Canada

The flow properties of ..beta..-Zr-Nb (Cb) alloys were investigated by means of compression testing in the strain rate range 10/sup -1/ to 10/sup -5/ s/sup -1/ and from 725 to 1025/sup 0/C. The flow curves obtained on Zr-Nb alloys containing 10, 15 and 20 pct Nb exhibited flow softening, and the magnitude of this effect decreased as the temperature was increased. All three alloys also exhibited anneal hardening, i.e. an increase in flow stress at 825/sup 0/C with annealing time at 1000/sup 0/C. Neither the flow softening, nor the anneal hardening could be associated with environmental effects, as in Zr-Mo alloys, nor could they be attributed to texture changes or to the occurrence of dynamic recrystallization. On the basis of X-ray and microprobe investigations, as well as grain size measurements, it is concluded that the anneal hardening is due to the combined effect of grain growth and the formation of solute clusters during annealing. The occurrence of flow softening is attributed to the destruction of the solute clusters by straining. Stress-strain curves were also determined for Zr-2.5 pct Nb. Unlike the high Nb alloys, these materials exhibited neither flow softening nor anneal hardening. The flow stresses were found to be highly strain rate dependent, with stress sensitivities of about 5.5 for yielding and 4.5 for steady state flow.

• OSTI ID: 6298482
• Journal Information: Metall. Trans., A; (United States), Journal Name: Metall. Trans., A; (United States) Vol. 10A:5; ISSN MTTAB
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210000 -- Nuclear Power Plants
36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ANNEALING
CHEMICAL COMPOSITION
CRYSTAL STRUCTURE
GRAIN SIZE
HARDENING
HEAT TREATMENTS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NIOBIUM ALLOYS
POWER REACTORS
REACTORS
RECRYSTALLIZATION
SIZE
STRAIN RATE
STRESSES
YIELD STRENGTH
ZIRCONIUM ALLOYS
ZIRCONIUM BASE ALLOYS