Improvements in strength and ductility of FeAl-ZrB2 by rapid solidification

This paper reports on Fe-35Al alloys containing various amounts of ZrB2 prepared by melt spinning and the microstructure and its stability examined. The mechanical properties are evaluated both on as cast materials as well as after high temperature heat treatments. The ZrB2 additions lead to a dramatic increase in hardness and strength. In addition, small amounts of ZrB2 lead to significant increases in ductility. Because the microstructure is fairly stable, these improvements in properties are maintained even after high temperature exposures. Alloys with up to about 1%ZrB2 have the dispersoid particles arranged in an imperfect cellular microstructure after rapid solidification. The cell walls contain many fine particles and are efficient barriers against dislocation propagation. Strain occurs as dislocations escape through gaps in the imperfect cell walls at a stress level that is controlled by the size of these gaps