Ultrasonic machining of Al<inf>2</inf>O<inf>3</inf>/LaPO<inf>4</inf> composites

Al2O3/LaPO4 composites of varying compositions were drilled on an ultrasonic machine with low carbon steel tools (solid and hollow), in order to evaluate the response to machining. Vickers hardness for different compositions indicate critical load dependency on LaPO4 content. Significance of LaPO4 content on material hardness highlights the critical content for good sinterability. X-ray diffraction was done to study the phase content. Acoustic emission (AE) signals emitted by the work piece during machining was also analyzed. Ultrascan inspection was carried out to check for any internal defects. The data presented in the paper illustrate the significance of LaPO4 addition on machinability of Al2O3/LaPO4 composites in terms of MRR, AE response and hole geometry and associated defects. © 2007 Elsevier Ltd. All rights reserved.