Study of the Direct Metal Deposition of AA2024 by ElectroSpark for Coating and Reparation Scopes

Abstract

ElectroSpark Deposition (ESD) is a pulsed micro-welding process that is capable of depositing wear and corrosion resistance deposit to repair, improve, and to extend the service life of the components and tools. Major new applications have taken place in gas turbine blades and steam turbine blade protection and repair, and in military, medical, metal-working, and recreational equipment applications. In this study, the ESD technique was exploited to fabricate 2024 aluminum alloy deposit on a similar substrate. The deposits were deposited using different process parameters. Heat input was varied on three levels. The outcoming microstructure was analyzed by optical and scanning electron microscopies. The deposit was characterized by the overlapping of layers with a mixed microstructure. The average hardness was independent from the process parameters. Both porosity inside the deposits and cracks at the deposit/substrate interface were detected. The porosity lowered with the heat input and increased the average length of cracks.

Repairing 2024 Aluminum Alloy via Electrospark Deposition Process: A Feasibility Study

“…e electrospark deposition process parameters are shown in Table 2, where E is the value of the electric arc pulse energy in Joule. ese parameters are based on a previous study of Leo et al [36].…”

“…e main defects detected in the analyzed fillings were voids with different morphologies and microcracks that extended both perpendicularly and parallel to the substrate/filling interface. In particular, the typical voids identified within the fillings had Advances in Materials Science and Engineering three geometries, that is, small spherical voids (gas porosity), large, random-shaped voids (bridging porosity), and thin void layer (laminar porosity) [36]. e formation of these discontinuities depended strongly on the amount and localization of the fused material.…”

“…e formation of these discontinuities depended strongly on the amount and localization of the fused material. During the manual deposition, the selected electrical parameters, the distance of the electrode to workpiece surface, and the force on the electrode did not remain constant during the deposition process [19,36]. All the previous aspects changed the quantity of the metal that melted and/or evaporated.…”

“…In addition, columnar grain structure grew perpendicularly to the substrate (Figures 6(a) and 6(b)). ese columnar grains grew epitaxially along the crystallographic direction of previously solidified grain, through multiple layers, producing microstructure normal to the deposition layers [10,36,38,42]. e coating microstructure was fine due to the high cooling rate [15,16].…”

“…e relationship between process parameters and the deposit structure has been also investigated [33][34][35][36]. Only few studies are related to the utilisation of ESD as a repair technology.…”