Residual stress distribution in a Ti-6Al-4V alloy deposited using Additive Friction Stir Deposition

Additive Friction Stir Deposition (AFSD) is an innovative method in additive manufacturing that creates parts in a solid state, avoiding the melting phase. This solid-state process results in reduced residual stresses and a much lower likelihood of defects such as porosity and hot-cracking, which are common in traditional fusion-based metallic additive manufacturing techniques. In this study, residual stress distribution in a Ti-6Al-4V alloy deposited using Additive Friction Stir Deposition (AFSD) through the contour method will be discussed. The AFSD block examined is quite large, measuring 200 mm × 35 mm × 67 mm. The stress magnitudes are about 13% of the material's yield strength. In the transverse direction of the deposition, residual stresses are concentrated near the core of the deposit, showing tensile values between 100 and 150 MPa, while compressive stresses are observed at the deposited surface, reaching -100 to -150 MPa. In the build direction, residual stresses in the middle of the block remain close to zero (ranging from -40 to +40 MPa). These findings demonstrate the AFSD process's effectiveness in achieving low residual stress levels, which is advantageous for maintaining structural integrity and performance in critical applications.