Varestraint weldability testing of additive manufactured alloy 718

The weldability in terms of susceptibility towards hot cracking of selective laser melted (SLM) Alloy 718 was investigated and wrought Alloy 718 was used as reference material. Varestraint testing was carried out by means of investigating the weldability in three conditions; (1) SLM as-built, (2) hot isostatic pressing at 1160°C at 105 MPa for 3 h and (3) wrought Alloy 718 in the mill-annealed condition. The material exhibited intergranular cracking in all three conditions; however, the SLM HIPed condition had an increased magnitude of crack susceptibility at all strain levels. The increased sensitivity of the HIPed material was due to the significantly larger grain size in comparison. The SLM as-built condition showed the same degree of cracking as the wrought material.