EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Wire arc additive manufacturing (WAAM) is a recently developed technology based on gas tungsten arc welding (GTAW) process. It allows fabrication of 3D metal components via progressive melting and layer-by-layer solidification of a metal wire. Several wires supplied at a variable feed rate allow to carry out in-situ alloying during manufacturing and produce components with chemistry-microstructure-properties gradient. In this project, additive manufacturing of new and repair of old machine parts made of Ni-Cu alloys were conducted using a single feed wire. Two Ni-Cu alloys with a varying composition (Ti, Mn, Al and C contents) were deposited on a substrate plate with a wide range of welding parameters (travel speed, wire feed rate). The solute atom concentrations and particle number density values were modified using various post processing heat treatment schedules. A comprehensive study of the microstructure, mechanical properties, wear and corrosion resistance of the Ni-Cu alloy components has been conducted. For similar deposition and heat treatment conditions, an alloy with higher C and Al, and lower Mn contents exhibited a higher number density of >20 nm TiC particles, higher number density of <20 nm γ′-Ni3(Al, Ti) particles, and, associated with these, superior hardness, tensile strength, strain hardening rate, toughness and wear resistance. The effects of alloy composition and heat treatment on the microstructure-properties relationship in the studied Ni-Cu alloys are discussed. The hot-rolled Ni-Cu plate was used as a reference for mechanical properties, wear and corrosion resistance of the fabricated samples. The results showed that, although the strength of the deposited alloys was lower than this of the hot rolled plate, the toughness, wear and corrosion resistance of depositions were higher almost in all WAAM conditions.