CARBIDE TOOL WEAR MECHANISM IN TURNING OF INCONEL-718 SUPERALLOY

Wear surfaces of the cutting tools are analyzed to study the wear mech anism of cemented carbide tools in turning of Inconel 718 superalloys. SEM and EPMA analyses indicated that the wear of carbide tools during high speed turning condition (V = 35 m min (-1)) was caused by diffus ion of elements (Ni or Fe) in workpiece into tool's binder (Co) by a g rain boundary diffusion mechanism. This action weakened the bonding st rength between carbide particles (WC, TiC, TaC) and the binder (Co). T he carbide particles were then detached out of the cemented carbide to ol by high flow stresses. The proposed grain boundary diffusion mechan ism is also confirmed by theoretical analysis.