This study examines the effect of tool rotational speed on the microstructure and dry sliding wear behavior of brass–tungsten (brass/W) surface composites fabricated through friction stir processing. Microstructural analysis confirmed a uniform distribution of tungsten particles within the stir zone, with no observable clustering. Improved properties were achieved at a lower traverse speed of 40 mm/min combined with a higher rotational speed of 1168 rpm, which promoted finer grain formation (~4