Repair & maintenance by Metal Additive Manufacturing process on Titanium alloy parts

Abstract

The CRO2 project* deals with both the aircrafts’ parts repair & maintenance and the Additive Manufacturing by metal powder Directed Energy Deposition **. Repairing parts in the aerospace industry is a potential application for additive manufacturing technologies. It’s thus possible to reduce operating losses and to avoid waste of costly and strategic raw materials. CRO2 proposes a pre-industrial development to rebuild lost shapes and functions of Ti64 alloys structures as example in air bled piping. Laser Metal Deposition (DED) process was used for Ti64 parts manufacturing. Tensile and fatigue tests were performed on several samples to characterize the AM material. The mechanical properties of the tested samples are comparable to those of the laminate Ti64 and their microstructure is typical of additive manufacturing. The reliability of the proposed technique, compared to welding repairs’ process, has been successfully demonstrated using aircraft environmental qualification tests at high temperature and pressure carried out on thin representative pipings. (*) CRO2: Cost Repair Overhaul Optimization (**) DED AM: Directed Energy Deposition Additive Manufacturing

A Grey-Box Model of Laser Powder Directed Energy Deposition for Complex Scanning Strategy

“…Simultaneously, the powder is conveyed into the melt pool and rapidly melts, producing a raised track as a result of the added material. While many studies have already demonstrated the ability and effectiveness of DED in restoring damaged components [4][5][6] or generating near-net-shaped parts [7], there are a number of open issues. The specific mechanism of material addition may induce high thermal gradients in the repaired part, which can affect the microstructure of the components, and the fast cooling rate generates residual stresses that can lead to distortion of the part [8,9].…”