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@PHDTHESIS{Rdler:855249,
author = {Rödler, Georg},
othercontributors = {Schleifenbaum, Johannes Henrich and Gumbsch, Peter},
title = {{E}ntwicklung des selektiven {L}aserstrahlschmelzens für
{A}l-{N}i-{L}egierungen; 1. {A}uflage},
school = {RWTH Aachen University},
type = {Dissertation},
address = {Aachen},
publisher = {Apprimus Verlag},
reportid = {RWTH-2022-10111},
series = {Ergebnisse aus der Lasertechnik},
pages = {1 Online-Ressource : Illustrationen, Diagramme},
year = {2022},
note = {Weitere Reihe: Edition Wissenschaft Apprimus. -
Druckausgabe: 2022. - Auch veröffentlicht auf dem
Publikationsserver der RWTH Aachen University; Dissertation,
RWTH Aachen University, 2022},
abstract = {In times of climate change, reducing emissions is a key
aspect of the research done in the transportation industry.
As one of the most important lightweight materials,
aluminium occupies a crucial role in this regard. By
increasing the functional properties of current aluminium
alloys, manufacturers could, therefore, decrease the
component weight, thereby reducing emissions. The weight
canbe lowered by either utilizing a more lightweight design
or alternatively substituting iron-based components for the
aluminium ones. It is challenging to process high-strength
aluminium alloys with additive manufacturing because they
are prone to hot-cracking. “Defect-free” manufacturing
can, therefore, only be accomplished by using complex
additions such as nano particles or rareearth elements. Due
to their documented resistance against hot-cracking as well
as their mechanical properties, Al-Ni-alloys based on the
α-Al + Al₃Ni eutectic system are promising candidates for
investigationwith additive manufacturing.Within this thesis
a comprehensive characterization of the microstructural and
mechanical propertiesof Al-Ni-alloys in the additive
manufactured state is being conducted for the first time.
Also, the effect of selected strengthening agents on
additively manufactured components is being investigated.
The following alloys are taken into consideration in the
scope of the thesis: AlNi7.5,AlNi7.5Cu0.5, AlNi7.5Cu2.0,
AlNi7.5Zr0.5 and AlNi7.5Mg1.0Si0.5 (values refer to Wt.
$\%).$ By achieving certain thresholds of the mechanical
properties (ultimate tensile strength at room
temperature/250 °C: 500 MPa/150 MPa), these experiments
shall lay the foundation for future researchas well as for
the application of Al-Ni alloys as structural components.
Within parameter studies conducted with laser powder bed
fusion, it can be confirmed that Al-Ni-alloyscan be
processed (crack-free; part density ≥ 99.9 $\%)$ with
additive manufacturing. The eutectic phases α-aluminium and
Al₃Ni can be detected. The solidification structure within
the melt tracks is characterized by a cellular Al₃Ni
structure embedded within an α-aluminium matrix. Throughout
all alloys and states considered in this thesis, the tensile
properties determined demonstrate a comparably high strength
with a maximum value of 556 MPa. This finding also applies
for investigations conducted at elevated temperatures. In
particular, the addition of 0.5 Wt. $\%$ Zr can thermally
stabilize the alloy and leads to the determination of an
ultimate tensile strength of 214 MPa at 250 °C.Among the
alloys investigated, the elongation at failure was reduced
when the testing temperature is increased above 150 °C
because of an embrittlement of the grain boundaries. An
exception inthis regard is the alloy AlNi7,5Mg1,0Si0,5. When
Mg and Si are added, comparably ductile failurebehaviour can
be achieved at elevated temperatures. Furthermore, the light
weight potential of additively manufactured Al-Ni-alloys is
being demonstrated by the fabrication of complex part
geometries.},
cin = {421510},
ddc = {620},
cid = {$I:(DE-82)421510_20170406$},
typ = {PUB:(DE-HGF)11 / PUB:(DE-HGF)3},
doi = {10.18154/RWTH-2022-10111},
url = {https://publications.rwth-aachen.de/record/855249},
}
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