On the evaluation of global laser-induced effects on a medical Ti-6Al-4Valloy by non-destructive techniques

Ti6Al4V ELI alloy is widely used for the fabrication of a wide range of load-bearing implants. Surface modification by laser shock processing (LSP) has demonstrated the capability to generate roughness of clinical interest, being the control of the surface and subsurface microstructural changes relevant to the intended applications. This work is aimed to compare the induced effects by scanning electron microscopy (SEM) and thermoelectric power (TEP) techniques to sense the subtle material variations such as local texture, increased dislocation density, hardening and residual stresses degree in a non-destructive way. For comparative purposes, synchrotron radiation X-ray diffraction (SR-XRD) experiments were also carried out to determine the residual stress state, The magnetic flux density (MFD) measurements demonstrate that the non-contact technique is very sensitive to the compressive residual stresses with increasing the severity of the laser treatment parameters, while the TEP contacting results are closely related to grain size, cracks, anisotropy, and work hardening.