Effects of cutting depth on the surface microstructure of a Zn–Al alloy during ultra-precision machining

The microstructural changes and phase decomposition at the surface of an ultra-precision machined Zn–Al based alloy were studied using optical microscopy, back-scattered electron microscopy, electron back-scattered diffraction and X-ray diffraction techniques. It was found that with increasing DoC the phase decomposition was accelerated and further increasing DoC might cause a microstructural recovery on the surface of the UPM specimen. UPM induced phase decomposition was discussed in relation to the structural evolution of the chips.