Properties of zirconium alloys and their applications in light water reactors (LWRs) - Materials' Ageing and Degradation in Light Water Reactors - page 106

(1986), and add modelling equations for the recovery process. Bourdiliau
et al . (2010) go a step further and show that there is a direct relation between
recovery of hardness and recovery of ultimate tensile stress (UTS) for both
SRA Zircaloy-4 and Zr1Nb. However the recovery for Zr1Nb is more slug-
gish than for Zircaloy-4, as shown in Fig. 4.19. Zr1Nb does not fully recover
the irradiation-induced hardening, primarily due the effects of the thermally
stable, irradiation-induced phase which forms in that alloy.
Post-irradiation annealing also has effects on irradiation-affected
SPPs. The observed phenomena give important insights into, for instance,

(a)

320

After creep tests at 420°C
Annealing at 350°C

310

300
290
280
270
260
250
240
230
220

Recovery law at 350°C

Annealing at 400°C

Recovery law 400°C

Annealing at 420°C

Recovery law 420°C

Nonirradiated (no annealing)

0 1000 2000 3000

Time (h)

4000 5000

(b)

250

After creep tests at 400°C
Annealing at 350°C

230

Recovery law at 350°C

Annealing at 400°C

Recovery law at 400°C

￿ ￿ ￿ ￿ ￿ ￿

Annealing law at 450°C

210

Recovery law at 450°C

190

170

Nonirradiated (no annealing)

150

0 500 1000 1500 2000 2500 3000 3500

Time (h)

4.19 Comparison of the hardness recovery of (a) SRA Zircaloy-4 and
(b) RXA Zr1Nb. (Source: Reprinted, with permission, from Bourdiliau
et al. (2010), copyright ASTM International, 100 Barr Harbor Drive, West
Conshohocken, PA 19428.)