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Selective laser melting (SLM) is a 3D printing technology suitable for manufacturing high-precision metal parts with complex geometries. At present, the research on SLM technology to produce high performance, complex structures made of superalloy parts has become the focus of aerospace and other fields. In this work, the microstructure, microhardness, and tensile strength of an Inconel 718 superalloy synthesized using SLM technology were first investigated. Then, the wear characteristics of the alloy at various temperatures were examined by multifunctional friction and wear testing equipment. Finally, a thorough analysis of the wear damage mechanisms of the materials over a wide temperature range was performed. The grains of the Inconel 718 superalloy formed by SLM developed as columnar grains that were more evenly and firmly dispersed along the horizontal axis. The material had a slightly greater microhardness in the vertical plane (HV 1 =346) than in the horizontal plane (HV 1 =324). A tensile test revealed that the horizontal tensile strength of SLM-formed Inconel 718 alloy was 50.1 MPa higher than that in the vertical direction, while the elongation was 0.14 % lower than the latter. The fracture mechanism of the material presented a fracture type dominated by microporous aggregation. A friction wear test showed that the friction wear coefficient of the SLM-formed Inconel 718 alloy gradually decreased with temperature. Abrasive wear, oxidative wear, and adhesive wear were the main wear mechanisms for the material during wear testing in the high temperature environments. The wear surface of the alloy material generated an oxide layer at 650 °C, which was effective in lowering friction and wear. [ABSTRACT FROM AUTHOR]

In this study, Inconel 718 alloy samples were prepared by laser cladding deposition technology, and GCr15 steel balls were selected as the friction pair. The tangential fretting wear tests were conducted in ball-on-flat point contact mode using a self-developed multifunctional fretting wear tester. The damage evolution law of fretting damage with the number of cycles for laser cladding Inconel 718 alloy was investigated at room temperature (RT) and 400 °C. The obtained results reveal that the coefficient of friction curves and energy dissipation value in the process of fretting wear first increased, then decreased, and finally reached a stable state with increasing cycles. At room temperature, the fretting running states gradually changed from mixed slip regime (MSR) to gross slip regime (GSR). There was clear spalling in the fretting damage zone, and a large mass of wear debris was formed on the worn surface. As the test time continued, the width and depth of the wear marks gradually increased, the volume of material wear increased, and the wear damage of the material gradually aggravated. When the test temperature was 400 °C, the fretting was running in the MSR. As the number of cycles increased, spalling and adhesion of wear debris occurred in the fretting damage zone. The main mechanisms of fretting wear were oxidation wear, abrasive wear, fatigue wear and adhesive wear. [ABSTRACT FROM AUTHOR]

• The fretting wear mechanisms of Inconel 718 alloys deposited by laser cladding in different temperature were analyzed. • In PSR, the wear damage mainly shows elastic–plastic deformation, fatigue wear and abrasive wear. • In MFR and GSR, the wear damage was mainl combined with fatigue wear, peeling, adhesive wear and oxidative wear. • High temperatures induces oxidation reactions during friction and slow down the wear of the material. Fretting tests were performed on an Inconel 718 superalloy against GCr15 steel in a range of 25 ℃ < T < 400 ℃ to investigate the wear mechanism of the laser cladding-deposited Inconel 718 superalloy over a wide temperature range. The results show that when the displacement amplitude was 15 μm, the fretting was running in a partial slip regime (PSR), and the wear damage mainly showed elastic–plastic deformation, fatigue wear and abrasive wear. When the displacement amplitude increased to 100 μm, fretting occurred in a mixed slip regime (MSR) and gross slip regime (GSR). With continuous fretting wear, the dissipated energy of the material decreased gradually with increasing temperature in a stable state. The wear damage was mainly combined with fatigue wear and peeling. When the temperature was 100 ℃, the coefficient of friction (COF) value in the stable state was large. As the temperature increased, adhesive wear and oxidative wear gradually predominated in the fretting tests. The effect of high temperature easily formed an adhesive layer on the worn surface with wear reduction, especially at a high displacement amplitude. [ABSTRACT FROM AUTHOR]