Effect of aluminum addition on ductility and yield strength of Fe/sub 3/Al alloys with 0.5 wt % TiB/sub 2/

Studies have been conducted of the mechanical properties of Fe/sub 3/Al alloys containing 24 to 30 at.% Al, to which 0.5 wt% TiB/sub 2/ was added for grain refinement. In tensile tests conducted at room temperature, it has been found that, as the aluminum content is increased, the yield strength decreases sharply from 760-310 MPa. The decrease in yield strength is accompanied by a four-fold increase in room-temperature ductility. Ordered iron aluminides (containing no disordered α phase) showed a clear increase in yield strength with temperature above 3000C. Their strength reached a maximum around 6000C, above which it decreased sharply. All these results are discussed and correlated with stability of superlattice dislocations as a function of aluminum content