Citation: Nie, D.; Du, R.; Zhang, P.;
Shen, F.; Gu, J.; Fu, Y. Force and
Microstructure Variation of SLM
Prepared AlMgSc Samples during
Three-Point Bending. Materials 2022,
15, 437. https://doi.org/10.3390/
ma15020437
Academic Editors: Adam Grajcar and
Ludwig Cardon
Received: 11 November 2021
Accepted: 15 December 2021
Published: 7 January 2022
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Article
Force and Microstructure Variation of SLM Prepared AlMgSc
Samples during Three-Point Bending
Daming Nie
1
, Ruilong Du
1,
*, Pu Zhang
1
, Fangyan Shen
1,
*, Jason Gu
2
and Yili Fu
3
1
Interdisciplinary Innovation Research Institute, Zhejiang Lab, Hangzhou 310000, China;
niedaming@zhejianglab.com (D.N.); zhangpu@zhejianglab.com (P.Z.)
2
Department of Electrical and Computer Engineering, Dalhousie University, Halifax, NS B3H 4R2, Canada;
jason.gu@dal.ca
3
State Key Laboratory of Robotics and System, Harbin Institute of Technology, Harbin 150000, China;
meylfu@hit.edu.cn
* Correspondence: duruilong@zju.edu.cn (R.D.); shenfangyan@zhejianglab.com (F.S.)
Abstract:
Lightweight parts manufactured by metal selective laser melting (SLM) are widely applied
in machinery industries because of their high specific strength, good energy absorption effect, and
complex shape that are difficult to form by mechanical machining. These samples often serve in
three-dimensional stress states. However, previous publications mainly focused on the unidirectional
tensile/compressive properties of the samples. In this paper, AlMgSc samples with different geo-
metric parameters were prepared by the SLM process, and the variation of force and microstructure
during three-point bending were systematically investigated. The results demonstrate that the defor-
mation resistance of these samples has good continuity without mutation in bending, even for brittle
materials; the bending force-displacement curves exhibit representative variation stages during the
entire bending process; the equivalent bending strength deduced from free bending formula is not
applicable when compactability is less than 67%. The variations of grain orientation and size of the
three representative bending layers also show regularity.
Keywords: SLM; additive manufacturing; bending deformation; grain orientation
1. Introduction
SLM manufactured parts occupy widespread application because of light
density [1–3]
and complex modeling, which present challenges in mechanical machining [
4
]. For example,
the SLM parts are manufactured into bracket connectors on the Airbus A350 XWB [
5
]
and could also be designed as cooling channels with optimized mechanical and heat
dissipation performance [
6
], which are employed in the combustion chambers or turbines
of aircraft engine. Yan et al. [
7
] studied the effect of porosity of Ti alloy SLM parts on
biocompatibility [
8
] and proved that they possess equivalent compressive strength to
human trabecular bones.
In this paper, AlMgSc was selected as the material of SLM parts. The microstruc-
tural variation of aluminum alloy at room temperature has been widely studied and
reported [9–11]
. Vu et al. [
12
] employed the process of Friction-Assisted Lateral Extru-
sion (FALEP) relative to Al-1050 alloy and successfully reduced the grain size more than
160 times
down to 600 nm under the imposed shear strain of 20. The simple shear texture
is obtained nearly parallel to the plane of the sheet. Rogachev et al. [
13
] analyzed the
effect of high-pressure torsion (HPT) on the microstructure and tensile properties of the
Al-10% La, Al-9% Ce, and Al-7% Ni alloys, showing the formation of nanocrystalline and
submicrocrystalline structures and the refinement of eutectic particles in aluminum alloys.
Yang et al. [
10
] investigated the cryogenic rolling (CR) process of T3003 aluminum alloy.
The results demonstrate that this process can significantly decrease the size of sub-grains
and second-phase particles and increase dislocation density. The initial Cube and R-Cube
Materials 2022, 15, 437. https://doi.org/10.3390/ma15020437 https://www.mdpi.com/journal/materials
