Experimental observations on surface roughness, chip morphology, and tool wear behavior in machining Fe-based amorphous alloy overlay for remanufacture

Fe-based amorphous alloy, a new-type material, was developed as a special-purpose welt overlay for remanufacture. It was deposited on the worn-out part for resuming and upgrading part performance. The microstructure characteristics of the overlay was characterized, including microstructure, phase composition, thermostability, and microhardness. In order to get a comprehensive insight to the machining process of amorphous overlay, this paper presents an experimental investigation into the effect of various machining parameters and tool geometry (Edge) on the surface roughness, tool wear, chip morphology, and surface damage. Comparing larger rake angle of 15A degrees and smaller nose radius of 0.4 mm with 5A degrees and 0.8 mm at the same cutting parameters, we found that larger rake angle of 15A degrees and smaller nose radius of 0.4 mm increased the R (a) surface roughness parameter. In the tests, crater wear was not observed, and the friction and wear on the minor cutting edge wear were heavy due to the spring back of the machined surface. In brief,abrasion, adhesion, fatigue, and chipping are the main wear mechanism. As the feed rate reduced and the depth of cut increased (from feed rate = 0.06 mm/rev and depth of cut = 0.3 mm to feed rate = 0.09 mm/rev and depth of cut = 0.2 mm), a number of physical changes occurred in the chip including reduced distance between serrations, increased shear band angle, and changed chip morphology from spiral to ribbon shape. The results show that strain and strain rate rises in the chips' inside with the increase in cutting temperature. When the thermal softening exceeded strain hardening, the shear resistance decreased rapidly. Thus, the free surface of the chip presents the nodular and lamella structure. It was noted that specimens generated by larger rake angle of 15A degrees and smaller nose radius of 0.4 mm showed poor surface roughness as well as extensive surface damage.