Characterisation of relaxation of residual stresses due to heat treatment in additively manufactured Laser Beam Melted (LBM) AISI 316L

Additive manufacturing, otherwise know as 3D printing is gaining in industrial relevance as a manufacturing technique partially due to the ability to fabricate complex geometries. Laser Beam Melting is one of the techniques used for additve manufacture of metallic components. The laser locally melts a bed of powder material generating high temperature gradients which can generate high residual or "locked-in" stresses. These residual stresses are usually reduced through heat treatments which minimise the risk of distorsion and detelerious influences on fatigue behaviour. Therefore it is important to understand the degree of stress relaxation achieved from the as-build condition in order to optimise the heat treatment for both residual stresses, distorsion and microstructure.