Comparison of the machinability of titanium alloy forging and powder metallurgy materials

In this paper, Ti-6Al-4V powder metallurgy (PM) material was prepared with hot isostatic pressing technology. In order to compare the machinability of the Ti-6Al-4V forging and PM materials, cutting experiments of Ti-6Al-4V forging and PM materials were done using a grooved tool involved in tool wear mechanisms, tool life, cutting temperature, cutting forces, and chip formation. In the machining of the PM material, chipping wear of the cutting tool became more severe due to the more severe microfluctuation of cutting forces, and adhesive wear turned to be slighter because of the influence of void on the tool-chip interface friction. Compared with the cutting tool average flank wear (VB) in the machining of the two materials, the tool life in the machining of the PM material was longer than that of the forging material. Taking into consideration cutting forces and cutting temperature, the better machinability was attributed to the smaller cutting forces, but the cutting temperature of the PM material was slightly higher than that of the forging material. In terms of the chip morphology, the void in the PM material made the lamella structure of the back surface more uniformly distributed and made the deformation coefficient greater.