Build Orientation Effects on Mechanical Properties of 316SS Components Produced by Directed Energy Deposition

Abstract

Laser Directed Energy Deposition (DED) is an additive manufacturing process whereby a laser fuses metal feed stock to the surface of a part. The process can be complete once to form a cladded layer or can be carried out numerous times to build complex three-dimensional structures. One major obstacle to the widescale acceptance of DED technology is the tightly coupled relationship between mechanical performance and process parameters.This study investigated the effects of layer orientation on the mechanical properties of 316L stainless steel (SS) parts fabricated via DED process. Quasi-static tensile tests were conducted on DED 316L SS specimens fabricated in orientation increments of 15 degrees with respect to the loading direction. Specimens were tested in their as-built condition without post process heat treatments. Yield, ultimate tensile strength (UTS), and maximum elongation measurement were taken, contributing to the ultimate finding that: Young’s Modulus is largely unaffected, yield stress may vary by 73 MPa corresponding to a 30 degree change in layer orientation, ultimate tensile strength does not show a strong statistical outcome based on layer orientation, and ductility shows a strong positive correlation to increases in layer angle with respect to axis of tensile stress.