Tool wear behaviour and workpiece surface integrity when turning Ti-6Al-2Sn-4Zr-6Mo with polycrystalline diamond tooling

The paper details the performance of a range of polycrystalline diamond (PCD) tools (∼1.3-39 μm average diamond grain size) when turning Ti-6Al-2Sn-4Zr-6Mo with 150 bar cutting fluid. The alloy is used for aeroengine components such as turbine discs due to its superior mechanical and elevated temperature properties. Tool life improved from ∼30 to 80 min with increasing grain size except with the ultra-coarse (∼39 μm) PCD grade, which failed via chipping/edge fracture after ∼8 min. In general, the principal wear modes were crater formation and workpiece adhesion. Workpiece integrity assessment showed no major subsurface damage with surface compressive residual stresses of ∼600 MPa.