Abstract
Laser micro–Raman spectroscopy was used to examine the silicon substrates plunge–cut by a round–nosed diamond tool under various conditions, and the results were compared with those of continuous diamond turning tests described in a previous paper. The results showed that the subsurface layer was partially transformed to amorphous, the extent of amorphization depending strongly on the depth of cut and tool rake angle. The Raman intensity ratio of the amorphous phase to the crystalline phase reaches maximum within the ductile–brittle transition region; while as the depth of cut increases or decreases from the ductile–brittle transition region, the intensity ratio decreases. It was also indicated that although a higher negative tool rake angle can achieve a larger critical depth of cut, it may cause more significant amorphization and subsurface damage than a lower negative rake angle.
