On the influence of physical vapor deposited thin coatings on the low-cycle fatigue behavior of additively processed Ti-6Al-7Nb alloy

The tensile and fatigue properties of laser powder bed fused Ti-6Al-7Nb are improved by physical vapor depo-sition (PVD). Thin coatings of titanium nitride (TiN), titanium carbonitride (TiCN), and silver-containing amorphous carbon (a-C:Ag) are deposited by magnetron sputtering. Tensile and strain-controlled low-cycle fa-tigue tests with various total strain amplitudes are performed. The coatings increase the tensile strength and decrease the breaking elongation. The low-cycle fatigue performance of the PVD-coated conditions, except for the a-C:Ag coating, is improved. The coatings considerably enhance tensile strength and fatigue resistance due to their high residual compressive stresses and increased surface hardness.

Automated summary

The tensile and fatigue properties of Ti-6Al-7Nb alloy processed by laser powder bed fusion can be improved by depositing thin coatings of TiN, TiCN, and a-C:Ag using physical vapor deposition (PVD) technique. These coatings enhance the tensile strength and fatigue resistance, except for the a-C:Ag coating, due to their high residual compressive stresses and increased surface hardness.