Rapid solidification of undercooled FeCoNiCu multi-principal element alloy: Mechanical and tribological properties

•A transition from dendrites to equiaxed grains was found at high undercooling.•The segregation of Cu element almost disappears at the largest undercooling.•An obvious improvement of mechanical property compared to the as-cast alloy was observed.•The effect of undercooling on the increasing wear resistance was analyzed in-depth.