The joint effect of laser and shear stress treatments for the surface strengthening of Zr alloys

In order to improve the surface strength, the structural evolution and mechanical properties of 47Zr-45Ti-5Al-3V alloys treated by laser and shear stress are investigated by X-ray diffraction (XRD), microhardness tester, and nanoindentation. The results indicate that the combined treatment of laser and shear stress is more advantageous than that of single laser or single shear stress to the surface strengthening of Zr alloys. α phase and β phase in the surface layer almost transform into fine β phase completely during laser treatment, which plays a fine grain strengthening effect. The followed treatment of shear stress can transform β phase into ω phase, which plays a dispersion strengthening effect, and induces a mass of dislocation which plays a dislocation strengthening effect. Higher plasticity and fine size of β phase are helpful to restrain the appearance of cracks during the treatment of shear stress.