Metal additive manufacturing, in particular Selective Laser Melting (SLM), emerged as a technology suitable for the industrial production of structural components featuring complex geometries, i.e. internal cooling cavities, like the ones typical of the aerospace and power generation industries. In this field, nickel-based superalloys are used in a wide range of critical applications, characterized by the occurrence of severe environmental conditions and elevated stresses. The SLM process parameters play a fundamental role both in determining the mechanical performances of the component, in particular the fatigue strength, but are also the key parameter for increasing the productivity of the process and thus the industrial spread of the technology. In the present work, it is presented an experimental investigation, through HCF tests on plain and notched specimens, fractographic examinations, and metallographic analyses, of the effects of productivity-oriented process parameters on fatigue strength, surface quality, and microstructural defects, namely hot tearing cracks and porosities, of the Inconel 718 alloy. The experimental approach, along with a theoretical investigation of the thermal field produced by the SLM process, will be used to define a feasible region in terms of scan velocity, laser power, layer thickness, and scan strategy.

Productivity-oriented process parameters effect of the fatigue strength of SLMed Inconel 718

macoretta g.
Primo
Writing – Original Draft Preparation
;
monelli b. d.
Secondo
Supervision
2021-01-01

Abstract

Metal additive manufacturing, in particular Selective Laser Melting (SLM), emerged as a technology suitable for the industrial production of structural components featuring complex geometries, i.e. internal cooling cavities, like the ones typical of the aerospace and power generation industries. In this field, nickel-based superalloys are used in a wide range of critical applications, characterized by the occurrence of severe environmental conditions and elevated stresses. The SLM process parameters play a fundamental role both in determining the mechanical performances of the component, in particular the fatigue strength, but are also the key parameter for increasing the productivity of the process and thus the industrial spread of the technology. In the present work, it is presented an experimental investigation, through HCF tests on plain and notched specimens, fractographic examinations, and metallographic analyses, of the effects of productivity-oriented process parameters on fatigue strength, surface quality, and microstructural defects, namely hot tearing cracks and porosities, of the Inconel 718 alloy. The experimental approach, along with a theoretical investigation of the thermal field produced by the SLM process, will be used to define a feasible region in terms of scan velocity, laser power, layer thickness, and scan strategy.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/1116822
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