Tailoring alloy 718 laser directed energy deposition process strategies for repair applications

Abstract

Laser-based directed energy deposition (LDED) for repair and sustainment has become a viable alternative to replace or complement traditional repair applications. Many a time, thin-walled structures cannot be repaired because of the heat intensive repair operations, which lead to excessive distortion or degradation of the parent material. To overcome repair challenges related to thin-walled structures, a low-energy process strategy with powder feedstock has been developed to reduce the heat-affected zone, reduce distortion, and produce a microstructure yielding higher microhardness values. On the other side of the repair spectrum, much larger surfaces may also need attention. In this case, a high-deposition rate process strategy may be more suitable to reduce lead-time and cost. To accommodate larger repairs, a high-deposition rate process strategy using wire feedstock has been developed. The high-deposition rate strategy is shown to be more cost-effective provided the target application and part geometry can accommodate the high-energy process. Validating these LDED repair strategies has been accomplished by analyzing the resulting distortion, presence of flaws or defects, microhardness, microstructure, and tensile properties. The process control offered by LDED through the ability to tailor the process-structure-property relationships of a material system depending on component geometry and application has put a new tool in place addressing many concerns related to traditional arc-based repair processes.

A Comparison of Microstructure and Microhardness Properties of IN718 Fabricated via Powder- and Wire-Fed Laser-Directed Energy Deposition

“…Several single-layer single-track experiments are performed to determine the optimal process parameters for both systems [ 19 , 20 ]. Compared to the powder-fed specimen, the wire-fed specimen shows a smooth and shiny metallic surface as depicted in Figure 4 c,d.…”

Putting 3D printing to good use—Additive Manufacturing and the Sustainable Development Goals

“…• Possibility to enhance product lifetime by printing spare parts (Durão et al, 2016;Ford and Despeisse, 2016) or by specific repair of critical sections via DED (Saboori et al, 2019;Jamieson et al, 2022;Arai et al, 2023), • Recycling of waste through waste-to-filament processes (Feeley et al, 2014;Ponis et al, 2021;Romani et al, 2021), and • More efficient use of resources through complex structures that need less material (Gebler et al, 2014;Sauerwein et al, 2019;Sun et al, 2021).…”

The Influence of Intralayer Porosity and Phase Transition on Corrosion Fatigue of Additively Manufactured 316L Stainless Steel Obtained by Direct Energy Deposition Process

“…Currently, most of the research activities using the WLAM process are related to Ti-based alloys, nickel-based superalloys, and carbon steels [ 14 , 27 , 28 ], while relatively few studies have been dedicated to austenitic stainless steels [ 11 ]. The attractive mechanical properties and corrosion resistance of austenitic stainless steel, and in particular of the 316L alloy, make them a promising choice as a structural material for AM technologies in common applications relating to the medical, nuclear, and aerospace industries [ 29 ].…”