Ultra-precision machining induced surface structural changes of Zn–Al alloy

Ultra-precision machining was carried out on a furnace cooled (FC) eutectoid Zn–Al alloy specimen using a new technology of single point diamond turning (SPDT). Microstructural changes and phase decomposition at the surface of the ultra-precision machined alloy specimen were investigated. It was found that the ultra-precision machining induced external stress resulted in decomposition of the ε phase and crystal orientation changes of the Zn-rich phases: η and ε, at the surface of the machined FC Zn–Al alloy specimen, which were in agreement with the tensile stress induced phase transformations and crystal orientation changes in the FC Zn–Al alloy specimen.