The mechanical properties of (Fe
1-xV
x)
3Al alloys including the Heusler-type Fe
2VAl (
x=1/3) have been investigated using high-temperature compression tests with attention to an increase in the D0
3(L2
1)-B2 transition temperature
Tc by the V substitution. The yield stress peak substantially shifts to higher temperatures with increasing
Tc and can be found at around 1270 K for Fe
2VAl. The strain rate sensitivity exponent
m is near zero in the temperature range where the plateau with a rather low yield stress appears, but rises sharply around the peak temperature, reaching
m=0.40 at 1300-1400 K for Fe
2VAl. Thus superplastic behavior is always expected to occur in the (Fe
1-xV
x)
3Al system when deformed at temperatures above that of the yield stress peak under a strain rate range of 10
-4-10
-3 s
-1. In spite of large-grained Fe
2VAl, the grain size becomes much finer after deformation up to a strain of 120%: from about 400 μm to 30 μm. Dynamic recovery and recrystallization process similar to that in Fe
3Al is proposed as the superplastic deformation mechanism.
View full abstract