The amorphous composite plate with a dimension of 60 mm×20 mm×2.5 mm was prepared by casting with copper mold.The friction stir welding was performed after preheating amorphous composite plate.With welding speed and shoulder drilling depth of 20 mm/min and 0.2 mm,respectively,the influences of rotational speed on microstructure and microhardness of amorphous composites were analyzed.The results reveal that the size of crystallization phase in the stirring zone is decreased after welding compared with that of the as-cast ones.The grains are refined gradually with the increase of rotational speed when the rotational speed is less than 1 000 r/min.However,when the rotational speed is more than 1 000 r/min,the enhanced thermal effect can coarsen grain size.Microhardness test reveal that the hardness of the stirring zone is lower than that of the as-cast ones.Besides,the hardness at 1 000 r/min is slightly higher than that of ones at 800 r/min,while the hardness at 1 200 r/min reaches the minimum value.