Impact of cryogenic Machining on the fatigue strength and surface integrity of wrought Ti6Al4V with equiaxed microstructure

The paper assesses the fatigue strength of the wrought Ti6Al4V titanium alloy with equiaxed microstructure after machining carried out under flood and cryogenic cooling conditions. Linear elastic fracture mechanics-based approaches are used to evaluate the effect of the surface integrity, modified through machining under different cooling strategies, on the material fatigue strength. Different cooling strategies can significantly influence the integrity of the machined surface, affecting factors such as microstructural alterations near the surface, surface finish, hardness, and residual stresses. The obtained results demonstrate that cryogenic machining improves surface integrity by refining the grain size and enhancing the surface finish and slightly enhancing the Ti6Al4V fatigue strength compared to flood cooling. The use of cryogenic machining is proving to be an environmentally friendly alternative to conventional machining that does not compromise fatigue performance and allows improved surface integrity, with potential benefits for the machining of critical titanium alloy components in various industrial applications.