Varestraint Testing of Selective Laser Additive Manufactured Alloy 718—Influence of Grain Orientation

Abstract

The effect of grain orientation on hot cracking susceptibility of selective laser additive manufactured Alloy 718 was investigated by Varestraint testing. Electron backscattered diffraction showed that cracks in heat affected zone (HAZ) of the welded samples occurred in high angle grain boundaries. The extent of HAZ cracking was smaller in samples tested parallel to the elongated grain orientation and larger in samples transverse to the elongated grain orientation. However, for solidification cracking in the weld metal, no significant difference with respect to grain orientation in the base metal was found.

Keywords

• selective laser melting
• alloy 718
• grain orientation
• varestraint testing
• hot cracking