Temperature dependence of the yield stress of an FeAl base alloy

The influence of temperature on the yield stress in Fe–45Al–4Cr–0.1Zr–0.02B (at.%) alloy after casting and homogenising (1273 K/72 h) was studied by means of transverse bending tests in argon atmosphere. Prior to studies the alloy was not annealed at low temperatures to remove retained vacancies. The yield stress shows an anomalous temperature dependence with a peak at 773 K. Measurements of electrical resistivity of alloy annealed at 1273 K/72 h and alloy additionally deformed (ε=0.5%) at the temperature of yield stress peak (773 K) showed close resistivity values, proving a similar concentration of defects in both cases. Thermal vacancies originating in mechanical test temperature are not the main reason a temperature anomaly of the yield stress in FeAl alloys.