Abstract
Mechanical properties of thermomechanically processed Fe–33at%Al and –38at%Al intermetallic alloys containing Zr (0.2–1.0 at%) were investigated by means of room-temperature tensile test and hardness test. The Zr-added ternary alloys showed fine-grained microstructure containing large (Fe, Al)12Zr τ1 phase particles, whereas the binary Fe–Al alloys showed a single phase microstructure consisted of coarse recrystallized grains. Yield stress was controlled by Hall–Petch rule and increased with decreasing grain size. Tensile elongation was controlled by the second-phase particles and decreased with increasing the volume fraction of the second-phase particles. Ultimate tensile stress was affected by the second-phase particles when the alloys were composed of fine grain size while it was affected by the grain size when alloys were composed of large grain size. Vacancy hardening which was significant in the alloys with high Al contents (i.e., Fe–38Al) was reduced by introducing the large τ1 phase particles.
