Machinability characteristics of wrought and EBM CoCrMo alloys

The Electron Beam Melting (EBM) CoCrMo alloy is currently utilized for the production of joint replacements and fixation devices thanks to its high strength, good wear and corrosion resistance, and excellent biocompatibility. Even if its use in the biomedical sector is intensive and it is usually subjected to various machining operations for the implants production after the rapid manufacturing step, the scientific literature lacks of comprehensive data about its machinability. Therefore, the objective of the paper is to investigate the machinability characteristics of the EBM CoCrMo alloy and compare it with the machinability of the wrought CoCrMo. Semi-finishing external turning tests were performed by using a commercial TiAlN coated tungsten carbide insert under a traditional mineral oil and water emulsion lubricating condition. Tool wear, surface integrity, and microstructure material analysis evidenced that the EBM alloy is more difficult to machine due to a more abrasive microstructure.