Mechanical properties of FeB and Fe2B layers estimated by Berkovich nanoindentation on tool borided steel

► Mechanical properties of the FeB and Fe2B layers were evaluated by nanoindentation. ► The thermal residual stresses across the boride layers were compressive. ► The presence of the indentation size effect was verified in both FeB and Fe2B layers. ► The FeB layer showed low fracture resistance with high brittleness.