The paper studies the possibility of using selective laser melting (SLM) to create quasi-crystalline materials based on the Al-Cu-Fe-Cr alloy. The influence of laser processing parameters on the microstructure and phase composition of single-layer and multilayer samples is studied. It is established that optimal SLM modes allow obtaining dense quasi-crystalline structures with a minimum content of undesirable phases.
Quasicrystals, which have unique physical and mechanical properties, attract considerable attention from researchers. However, their application is limited by the difficulty of producing massive products. SLM is a promising method for creating quasicrystalline parts of complex shape.
The study of the microstructure of quasicrystalline Al-Cu-Fe-Cr (QC) coatings produced by selective laser melting (SLM) revealed a dependence on the processing parameters. X-ray diffraction patterns showed that the coating produced by SLM consists predominantly of Al-Cu-Fe-Cr and α-Al (CuFeCr) quasicrystals. An increase in laser energy or coating thickness led to an increase in the volume fraction of QC i-Al, as well as QC d-Al65Cu20Fe10Cr5 and crystalline θ-Al2Cu. The formation of cracks during layer-by-layer deposition was studied.
It was found that with increasing laser power at the same number of layers, the pores and spherical particles decrease due to more complete melting. At the initial stage of production, the porosity and the number of spherical particles decrease significantly with increasing number of layers due to the slow solidification of the molten layer. However, after 10-20 layers, further increase in layers does not lead to a decrease in porosity, but large pores, microcracks and defects appear, especially when using lower laser power. A wave-like structure consisting of Al and QC phases is formed in the interphase zone between the substrate and the coating due to the Marangoni effect.
Quasicrystals, intermetallic compounds with long-range order without translational periodicity, attract attention due to their high strength characteristics, resistance to corrosion and wear. SLM, a modern method of additive manufacturing, allows creating components of complex shape with individual properties. The aim of this work is to study the effect of SLM parameters on the microstructure and phase composition of quasicrystalline Al65Cu20Fe10Cr5 coatings deposited on an aluminum substrate. The process of creating coatings with a thickness of 50 μm (1 layer) to 1 mm (20 layers) is studied.
Al-Cu-Fe-Cr alloy powder was used as the starting material for SLM. Laser processing parameters such as laser power, scanning speed and scanning step were varied. The microstructure and phase composition of the obtained samples were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD).
Single-layer samples obtained with optimal SLM parameters demonstrated high density and predominantly quasi-crystalline structure. Multilayer samples created by successive deposition and fusion of layers also had good adhesion between layers and retained quasi-crystalline structure. However, in some samples, formation of small amounts of undesirable phases, such as intermetallics, was observed.
SLM is a promising method for producing quasi-crystalline materials based on the Al-Cu-Fe-Cr alloy. Optimization of laser processing parameters allows the creation of dense single- and multi-layer samples with a predominantly quasi-crystalline structure. Further research is aimed at minimizing the formation of undesirable phases and improving the mechanical properties of the obtained materials.
Author: Yingqing Fu, Nan Kang, Hanlin Liao, Yang Gao, Christian Coddet
Institute:
Department of Materials Science and Engineering, Dalian Maritime University, Dalian 116026, China
University of Bourgogne Franche-Comté, IRTES EA7274, F-90100 Belfort, France