Machinability of difficult-to-machine materials can expect to be improved efficiently through weakening treatment by infiltration of detrimental elements into workpiece surface. This work studies the effect of element Te on alterations of microstructure and mechanical property of Inconel 718. An innovative method of Te infiltration is proposed to modify the Inconel 718 surface. The Te infiltration leads to delamination which depends on the treatment temperatures. A gradient distribution of Te occurs within the subsurface, and the intercrystalline telluride is characterized by TEM and EPMA. The mechanism of Te infiltration weakening will be discussed from physical and geometrical characteristics.