MSE 2024
Highlight Lecture
25.09.2024 (CEST)
Nb coating the CuNi3SiCr powders for low-power laser-based powder bed fusion processing of copper alloys
HB

Dr. Hossein Beygi Nasrabadi

FIZ Karlsruhe - Leibniz Institut für Informationsinfrastruktur

Beygi Nasrabadi, H. (Speaker)¹; Klotz, U.E.²; Skrotzki, B.¹; Tiberto, D.³
¹Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin; ²Forschungsinstitut Edelmetalle + Metallchemie (fem), Schwäbisch Gmünd; ³Fraunhofer-Institut für Werkstoffmechanik IWM, Schwäbisch Gmünd
Vorschau
21 Min. Untertitel (CC)

The laser-based powder bed fusion (PBF-LB/M) processing of high-density copper components is mainly performed with high laser powers due to the low laser absorption of copper powders [1-2]. Metal coating the copper particles has been investigated in this research as an approach for increasing the laser absorption of the feedstock and processing of highly dense copper alloys with low-power lasers. CuNi3SiCr powders were coated with the thin and uniform metallic shells of Nb (60 ± 10 nm) using a rotating Direct Current Magnetron Sputtering Physical Vapor Deposition (DCMS-PVD) reactor. Using such metal-coated particles, copper parts of 98.14% relative density were printed with the PBF-LB/M parameters of 200 W laser powers, 800 mm/s scanning speed, 55 µm hatch distance, and 25 µm layer thickness. The X-ray computed tomography (XCT), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS) investigations show that partial oxidation of Nb-coated particles is responsible for the development of lack-of-fusion holes between the printed layers. An approach based on the nanoindentation and electron backscattered diffraction (EBSD) measurements was utilized to evaluate the correlation between the crystallographic orientations and mechanical properties of the produced samples. In this approach, arrays of indentations (Fig. 1a) were applied on four planes of the samples trimmed in different directions. The EBSD images of these indentation regions reveal the location of each indent in colored grains of different orientations. Here, a microstructure with columnar grains and a high texture intensity of 9.2 has been observed in the plane perpendicular to the building direction. This plane comprises a mixture of red-, green-, and blue-colored grains, while the measured average hardness (H) and indentation modulus (Er) were increased from red grains to green and blue ones, respectively (Fig. 1b). Eventually, the nanoindentation load-displacement curves of [001], [101], and [111] grains (Fig. 1c) were utilized for modeling the elastoplastic features of the produced samples.

Abstract

Abstract

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