Study on the origins of residual stresses in Ti-6Al-4V processed by additive manufacturing

In additive manufacturing processes using laser beam melting high thermal gradients are generated, inducing residual stresses within the parts that may lead to deformations and, in worst cases, cracks. One of the materials that is the most sensitive to residual stresses is the Ti-6Al-4V alloy. In the present study, we focus on the various parameters that may control the genesis and build-up of the residual stress states. Dwell time and thermal conductivity, both influencing the heat evacuation, were studied. Higher thermal evacuation was find to rises residual stresses within the part. Then, the reliability of the energy density as a comparison parameter was investigated. Samples with the same energy densities but different power and scanning speed were elaborated. Energy density was shown as a non-reliable parameter to compare different processed parts