Analysis of the surface integrity induced by face milling of Laser Metal Deposited Ti-6A1-4V

摘要

The Laser Metal Deposition(LMD)is an additive manufacturing process which is gaining good competence in manufacturing and repairing complex functional parts.However,the produced parts require conventional machining operations in order to enhance the surface quality and the material properties.Due to the highly localized heat input experienced by the sample during the building process,significant variation of the local material properties can appear within the produced components.This could affect the machinability of the parts produced by the LMD process.This study aims to investigate the milling process and its effect on the resulted surface integrity of Ti-6A1-4V components produced by the LMD process.The heat treatment was performed in order to homogenize the microstructure of the material.The conventional Ti-6A1-4V was taken as a reference material sample.Depending on the cutting process parameters,the cutting forces and the surface roughness of the machined LMD parts were 10-40% and 18-65% respectively higher than the conventional samples.The compressive residual stress in the machined LMD samples were 11-30 % higher than the conventional specimen.These differences are related to microstructure and grain size differences between the tested parts.