The nanocrystalline FeMoSiB alloys with different grain sizes were pre
pared during the crystallization of their amorphous solids. The ultima
te tensile strength (UTS) and fatigue strength of amorphous and nanocr
ystalline materials were measured and compared with each ether. It is
found that the ratio of fatigue limit over UTS of amorphous materials
reaches the minimum and the maximum fatigue limit can be obtained in o
ne of these nanocrystalline materials. Abnormal Hall-Fetch relation wa
s also observed in these nanocrystalline materials.