The influence of laser parameters and scanning strategies on the mechanical properties of a stochastic porous material
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Published version
Author(s)
Type
Journal Article
Abstract
Additive manufacturing enables architectured porous material design, but 3D-CAD modelling of these materials is prohibitively computationally expensive. This bottleneck can be removed using a line-based representation of porous materials instead, with strut thickness controlled by the supplied laser energy.
This study investigated how laser energy and scan strategy affects strut thickness and mechanical strength of porous materials. Specimens were manufactured using varying laser parameters, 3 scan strategies (Contour, Points, Pulsing), 2 porous architectures and 2 materials (Titanium, Stainless Steel), with strut thickness, density, modulus, mechanical strength and build time measured.
Struts could be built successfully as low as 15° with a minimum diameter of 0.13 mm. Strut thickness was linearly related to the specific enthalpy delivered by the laser to the melt-pool. For a given stiffness, Titanium specimens built at low power/slow speed had a 10% higher strength than those built at high power/fast speed. The opposite was found in Stainless Steel. As specimen stiffness increased, the Contour Strategy produced samples with the highest strength:stiffness and strength:weight ratio. The Points strategy offered the fastest build time, 20% and 100% faster than the Contour and Pulsing strategies, respectively. This work highlights the importance of optimising build parameters to maximize mechanical performance.
This study investigated how laser energy and scan strategy affects strut thickness and mechanical strength of porous materials. Specimens were manufactured using varying laser parameters, 3 scan strategies (Contour, Points, Pulsing), 2 porous architectures and 2 materials (Titanium, Stainless Steel), with strut thickness, density, modulus, mechanical strength and build time measured.
Struts could be built successfully as low as 15° with a minimum diameter of 0.13 mm. Strut thickness was linearly related to the specific enthalpy delivered by the laser to the melt-pool. For a given stiffness, Titanium specimens built at low power/slow speed had a 10% higher strength than those built at high power/fast speed. The opposite was found in Stainless Steel. As specimen stiffness increased, the Contour Strategy produced samples with the highest strength:stiffness and strength:weight ratio. The Points strategy offered the fastest build time, 20% and 100% faster than the Contour and Pulsing strategies, respectively. This work highlights the importance of optimising build parameters to maximize mechanical performance.
Date Issued
2017-10-05
Date Acceptance
2017-06-16
Citation
Materials & Design, 2017, 131, pp.498-508
ISSN
0261-3069
Publisher
Elsevier
Start Page
498
End Page
508
Journal / Book Title
Materials & Design
Volume
131
Copyright Statement
© 2017 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (EPSRC)
Engineering & Physical Science Research Council (E
Imperial College London
Engineering & Physical Science Research Council (EPSRC)
Wellcome Trust
Grant Number
EP/N025059/1
EP/K027549/1
EP/K503733/1
Additive Manufacturing Network
N/A
088844/Z/09/Z
Subjects
Science & Technology
Technology
Materials Science, Multidisciplinary
Materials Science
Porous material
Architectured material
Mechanical testing
Scan strategy
Laser parameter
Powder bed fusion
IN-GROWTH CONSTRUCTS
UNIT-CELL APPROACH
LATTICE STRUCTURES
TITANIUM
BIOMATERIALS
TI-6AL-4V
MICROSTRUCTURE
MANUFACTURE
MORPHOLOGY
STRENGTH
Publication Status
Published
Date Publish Online
2017-06-17