Role of scanning strategy on residual stress distribution in Ti-6Al-4V alloy prepared by selective laser melting

Abstract

Selective laser melting (SLM) is one of additive manufacturing (AM) technologies used for directly fabricating 3D metal parts with complex shapes. However, the residual stress and the resultant deformation issues lead to the distortion and failure of SLM fabricated parts and impede the further application of this technology. In this research, a combination of the finite element simulation and experimental verification is proposed to study the effect of scanning strategies on the thermal behavior and residual stress distribution. Two kinds of mechanical boundary conditions are selected to investigate its effect on the residual stress in the mechanical simulation. The transient thermal simulation results demonstrate that the scanning strategies take a great influence on temperature field, however, molten pool size is hardly affected by the scanning strategies. In terms of residual stress simulation, 15° rotate scan strategy generates the smallest stress among the all scan strategies studied in this research. This conclusion is confirmed by experimental results. In addition, although there is still a difference between the numerical simulation and experimental result, mechanical simulation gives satisfactory residual stress trend compared with experiments.