Environmental Engineering Reference
In-Depth Information
2.6
2.4
2.2
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
Zr2.5Nb
E125
J
α
-Zr+
β
-Nb
-Zr+
-Nb+Zr(NbFe) 2
α
β
E110
M-5
α
-Zr+(ZrNb) 2 Fe+Zr(NbFe) 2
ZIRLO, Optim.-ZIRLO
E635
E635M
Zr0.25Sn0.75Nb0.25Fe
series
α -Zr+Zr 3 Fe+(ZrNb) 2 Fe
Test serie reported by Seibold
α -Zr+Zr 3 Fe
0
0.1
0.2
0.3
0.4
Fe content (%)
0.5
0.6
0.7
0.8
4.17 Zr-Nb-Fe ternary alloy phase diagram constructed from
information in Toffolon et al . (2002); Shishov et al . (2005); Nikulina et al .
(2006) - in Rudling et al . (2007).
form at 77°C (350K), and Zr 2 (Fe,Ni) SPPs do not become amorphous above
an irradiation temperature of about 100°C (453K) (see e.g. Griffi ths et al .,
1996). In addition, post-irradiation temperatures cause effects that give
insight to the microstructure stability.
Damage in the form of <a> loops appears to be stable in post-irradia-
tion annealing conditions to about 400°C (673K). Figure 4.18 (Adamson &
Bell, 1986) shows that 1 hour at 400°C is a threshold condition for damage
in size and density of <a> loops. Above that temperature, or quite likely
longer times at that temperature, results in a marked increase in loop size
and decrease in loop density. A temperature of 550°C (823K) for 1 h is suf-
fi cient to reduce the loop density to zero. This is accompanied by a dramatic
decrease in hardness, as discussed below. Complementary data (Cheng et al .,
1994) indicate no changes in <a> loops after 200 days at 316°C (588K).
On the other hand, <c> component dislocations are quite resistant to
change over the whole temperature range where <a> loops disappear. Yang
(1989) and Kruger (1990) have shown that 1 h at 560°C (833K) or 575°C
(848K) causes little or no change in <c> loop density or size. One hour at
675°C results in a 50% reduction in <c> loop density, while 1 h at 750°C
(1023K) results in removal of all loops.
Figure 4.18 indicates hardness decreases in concert with changes in the
<a> loop size and density. This is an indication that <c> loops do not have
infl uence on the hardness. A summary is given by Adamson (2006). An addi-
tional study (Ribis et al ., 2007 ), confi rms the results of Adamson and Bell
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