Abstract

The purpose of this research work is to characterize and inform the design of (mechanical) property-graded bulk structures made from a single metallic alloy via a laser powder bed fusion (LPBF) process, with an end goal of creating repeatable/reproducible functionally-graded additively manufactured (FGAM) parts. This paper specifically investigates the manufacture of stainless steel (SS) 316L structures via a pulsed selective laser melting (SLM) process, and the underlying causes of property variations (within a functionally-acceptable range) through various material characterization techniques. For this, a design of experiments spanning the volumetric energy density (VED) based process parameter design space was utilized to investigate the range of functionally-acceptable physical/mechanical properties achievable in SS 316L. Five sample conditions (made via different process parameter combinations) were down-selected for in-depth microstructure analysis and mechanical/physical property characterization; these were suitably selected to impart a wide and controllable property range (209–318 HV hardness, 90–99.9% relative density, and 154–211 GPa modulus). It was observed that property variations resulted from combinations of porosity types/amounts, martensitic phase fractions, and grain sizes. Based on these findings, property-graded standard test specimens were designed and manufactured for further investigation—tensile specimens having a monotonic hardness change along its gauge length, four-point bending specimens with varying elastic moduli as a function of the distance from the neutral axis, and Moore’s rotating beam fatigue specimens with moduli variations based on the distance from the center. Altogether, this work lays the foundation for understanding and designing the local and global mechanical performance of FGAM bulk structures.

References

1.
Parikh
,
Y.
, and
Kuttolamadom
,
M.
,
2021
, “
Selective Laser Melting of Stainless Steel 316L for Mechanical Property-Gradation
,”
Proceedings of the ASME 2021 16th International Manufacturing Science & Engineering Conference (MSEC 2021)
,
Cincinnati, OH
,
June 21–25
2.
Anstaett
,
C.
,
Seidel
,
C.
, and
Reinhart
,
G.
,
2017
, “
Fabrication of 3D Multi-material Parts Using Laser-Based Powder Bed Fusion
,”
Proceedings of the 28th Annual International Solid Freeform Fabrication Symposium
,
Austin, TX
,
Aug. 7–9
.
3.
Dehoff
,
R. R.
,
Kirka
,
M.
,
Sames
,
W.
,
Bilheux
,
H.
,
Tremsin
,
A.
,
Lowe
,
L.
, and
Babu
,
S.
,
2015
, “
Site Specific Control of Crystallographic Grain Orientation Through Electron Beam Additive Manufacturing
,”
Mater. Sci. Technol.
,
31
(
8
), pp.
931
938
.
4.
Tammas-Williams
,
S.
, and
Todd
,
I.
,
2017
, “
Design for Additive Manufacturing With Site-Specific Properties in Metals and Alloys
,”
Scr. Mater.
,
135
, pp.
105
110
.
5.
Marattukalam
,
J. J.
,
Karlsson
,
D.
,
Pacheco
,
V.
,
Beran
,
P.
,
Wiklund
,
U.
,
Jansson
,
U.
,
Hjörvarsson
,
B.
, and
Sahlberg
,
M.
,
2020
, “
The Effect of Laser Scanning Strategies on Texture, Mechanical Properties, and Site-Specific Grain Orientation in Selective Laser Melted 316L SS
,”
Mater. Des.
,
193
, p.
108852
.
6.
Traxel
,
K. D.
, and
Bandyopadhyay
,
A.
,
2020
, “
Naturally Architected Microstructures in Structural Materials Via Additive Manufacturing
,”
Addit. Manuf.
,
34
, p.
101243
.
7.
Loh
,
G. H.
,
Pei
,
E.
,
Harrison
,
D.
, and
Monzón
,
M. D.
,
2018
, “
An Overview of Functionally Graded Additive Manufacturing
,”
Addit. Manuf.
,
23
, pp.
34
44
.
8.
Niendorf
,
T.
,
Leuders
,
S.
,
Riemer
,
A.
,
Brenne
,
F.
,
Tröster
,
T.
,
Richard
,
H. A.
, and
Schwarze
,
D.
,
2014
, “
Functionally Graded Alloys Obtained by Additive Manufacturing
,”
Adv. Eng. Mater.
,
16
(
7
), pp.
857
861
.
9.
Popovich
,
V. A.
,
Borisov
,
E. V.
,
Popovich
,
A. A.
,
Sufiiarov
,
V. S.
,
Masaylo
,
D. V.
, and
Alzina
,
L.
,
2017
, “
Functionally Graded Inconel 718 Processed by Additive Manufacturing: Crystallographic Texture, Anisotropy of Microstructure and Mechanical Properties
,”
Mater. Des.
,
114
, pp.
441
449
.
10.
Mukherjee
,
T.
, and
DebRoy
,
T.
,
2019
, “
Printability of 316 Stainless Steel
,”
Sci. Technol. Weld. Join.
,
24
(
5
), pp.
412
419
.
11.
Kamath
,
C.
,
El-Dasher
,
B.
,
Gallegos
,
G. F.
,
King
,
W. E.
, and
Sisto
,
A.
,
2014
, “
Density of Additively-Manufactured, 316L SS Parts Using Laser Powder-Bed Fusion at Powers up to 400 W
,”
Adv. Manuf. Technol.
,
74
(
1–4
), pp.
65
78
.
12.
Smith
,
J.
,
Xiong
,
W.
,
Yan
,
W.
,
Lin
,
S.
,
Cheng
,
P.
,
Kafka
,
O. L.
,
Wagner
,
G. J.
,
Cao
,
J.
, and
Liu
,
W. K.
,
2016
, “
Linking Process, Structure, Property, and Performance for Metal-Based Additive Manufacturing: Computational Approaches With Experimental Support
,”
Comput. Mech.
,
57
(
4
), pp.
583
610
.
13.
Pinomaa
,
T.
,
Yashchuk
,
I.
,
Lindroos
,
M.
,
Andersson
,
T.
,
Provatas
,
N.
, and
Laukkanen
,
A.
,
2019
, “
Process-Structure-Properties-Performance Modeling for Selective Laser Melting
,”
Metals
,
9
(
11
), p.
1138
.
14.
Zhang
,
B.
,
Dembinski
,
L.
, and
Coddet
,
C.
,
2013
, “
The Study of the Laser Parameters and Environment Variables Effect on Mechanical Properties of High Compact Parts Elaborated by Selective Laser Melting 316L Powder
,”
Mater. Sci. Eng. A
,
584
, pp.
21
31
.
15.
Li
,
R.
,
Shi
,
Y.
,
Liu
,
J.
,
Yao
,
H.
, and
Zhang
,
W.
,
2009
, “
Effects of Processing Parameters on the Temperature Field of Selective Laser Melting Metal Powder
,”
Powder Metall. Met. Ceram.
,
48
(
3
), pp.
186
195
.
16.
Romano
,
J.
,
Ladani
,
L.
, and
Sadowski
,
M.
,
2015
, “
Thermal Modeling of Laser Based Additive Manufacturing Processes Within Common Materials
,”
Procedia Manuf.
,
1
, pp.
238
250
.
17.
Fayazfar
,
H.
,
Salarian
,
M.
,
Rogalsky
,
A.
,
Sarker
,
D.
,
Russo
,
P.
,
Paserin
,
V.
, and
Toyserkani
,
E.
,
2018
, “
A Critical Review of Powder-Based Additive Manufacturing of Ferrous Alloys: Process Parameters, Microstructure and Mechanical Properties
,”
Mater. Des.
,
144
, pp.
98
128
.
18.
Guo
,
Q.
,
Zhao
,
C.
,
Qu
,
M.
,
Xiong
,
L.
,
Hojjatzadeh
,
S. M. H.
,
Escano
,
L. I.
,
Parab
,
N. D.
,
Fezzaa
,
K.
,
Sun
,
T.
, and
Chen
,
L.
,
2020
, “
In-Situ Full-Field Mapping of Melt Flow Dynamics in Laser Metal Additive Manufacturing
,”
Addit. Manuf.
,
31
, p.
100939
.
19.
Cunningham
,
R.
,
Zhao
,
C.
,
Parab
,
N.
,
Kantzos
,
C.
,
Pauza
,
J.
,
Fezzaa
,
K.
,
Sun
,
T.
, and
Rollett
,
A. D.
,
2019
, “
Keyhole Threshold and Morphology in Laser Melting Revealed by Ultrahigh-Speed X-ray Imaging
,”
Science
,
363
(
6429
), pp.
849
852
.
20.
Suryawanshi
,
J.
,
Prashanth
,
K. G.
, and
Ramamurty
,
U.
,
2017
, “
Mechanical Behavior of Selective Laser Melted 316L Stainless Steel
,”
Mater. Sci. Eng. A
,
696
, pp.
113
121
.
21.
Mumtaz
,
K. A.
, and
Hopkinson
,
N.
,
2007
, “
Laser Melting Functionally Graded Composition of Waspaloy® and Zirconia Powders
,”
J. Mater. Sci.
,
42
(
18
), pp.
7647
7656
.
22.
Hengsbach
,
F.
,
Koppa
,
P.
,
Holzweissig
,
M. J.
,
Aydinöz
,
M. E.
,
Taube
,
A.
,
Hoyer
,
K.-P.
,
Starykov
,
O.
, et al
,
2018
, “
Inline Additively Manufactured Functionally Graded Multi-materials: Microstructural and Mechanical Characterization of 316L Parts With H13 Layers
,”
Prog. Addit. Manuf.
,
3
(
4
), pp.
1
11
.
23.
Attard
,
B.
,
Cruchley
,
S.
,
Beetz
,
C.
,
Megahed
,
M.
,
Chiu
,
Y. L.
, and
Attallah
,
M. M.
,
2020
, “
Microstructural Control During Laser Powder Fusion to Create Graded Microstructure Ni-Superalloy Components
,”
Addit. Manuf.
,
36
, p.
101432
.
24.
Parikh
,
Y.
,
Carter
,
J.
, and
Kuttolamadom
,
M.
,
2020
, “
Investigation of Porosity and Microstructure-Induced Property Variations in Additive Manufactured Stainless Steel 316L
,”
Proceedings of the ASME 2020 15th International Manufacturing Science and Engineering Conference (MSEC 2020)
,
Cincinnati, OH
,
June 22–26
.
25.
Abràmoff
,
M. D.
,
Magalhães
,
P. J.
, and
Ram
,
S. J.
,
2004
, “
Image Processing With ImageJ
,”
Biophotonics Int.
,
11
(
7
), pp.
36
42
.
26.
Gordon
,
J. V.
,
Narra
,
S. P.
,
Cunningham
,
R. W.
,
Liu
,
H.
,
Chen
,
H.
,
Suter
,
R. M.
,
Beuth
,
J. L.
, and
Rollett
,
A. D.
,
2020
, “
Defect Structure Process Maps for Laser Powder Bed Fusion Additive Manufacturing
,”
Addit. Manuf.
,
36
, p.
101552
.
27.
AlFaify
,
A.
,
Hughes
,
J.
, and
Ridgway
,
K.
,
2019
, “
Controlling the Porosity of 316L Stainless Steel Parts Manufactured Via the Powder Bed Fusion Process
,”
Rapid Prototyp. J.
,
25
(
1
), pp.
162
175
.
28.
Saeidi
,
K.
,
Gao
,
X.
,
Lofaj
,
F.
,
Kvetková
,
L.
, and
Shen
,
Z. J.
,
2015
, “
Transformation of Austenite to Duplex Austenite-Ferrite Assembly in Annealed Stainless Steel 316L Consolidated by Laser Melting
,”
J. Alloys Compd.
,
633
, pp.
463
469
.
29.
Tucho
,
W. M.
,
Lysne
,
V. H.
,
Austbø
,
H.
,
Sjolyst-Kverneland
,
A.
, and
Hansen
,
V.
,
2018
, “
Investigation of Effects of Process Parameters on Microstructure and Hardness of SLM Manufactured SS316L
,”
J. Alloys Compd.
,
740
, pp.
910
925
.
30.
Sun
,
Z.
,
Tan
,
X.
,
Tor
,
S. B.
, and
Yeong
,
W. Y.
,
2016
, “
Selective Laser Melting of Stainless Steel 316L With Low Porosity and High Build Rates
,”
Mater. Des.
,
104
, pp.
197
204
.
31.
Frick
,
J. P.
,
2000
,
Woldman's Engineering Alloys
,
ASM International
,
Materials Park, OH
.
32.
Hall
,
E.
,
1951
, “
The Deformation and Ageing of Mild Steel: III Discussion of Results
,”
Proc. Phys. Soc. B.
,
64
(
9
), pp.
747
753
.
33.
Hitzler
,
L.
,
Hirsch
,
J.
,
Heine
,
B.
,
Merkel
,
M.
,
Hall
,
W.
, and
Öchsner
,
A.
,
2017
, “
On the Anisotropic Mechanical Properties of Selective Laser-Melted Stainless Steel
,”
Materials
,
10
(
10
), p.
1136
.
34.
Cherry
,
J. A.
,
Davies
,
H. M.
,
Mehmood
,
S.
,
Lavery
,
N. P.
,
Brown
,
S. G. R.
, and
Sienz
,
J.
,
2015
, “
Investigation Into the Effect of Process Parameters on Microstructural and Physical Properties of 316L Stainless Steel Parts by Selective Laser Melting
,”
Int. J. Adv. Manuf. Technol.
,
76
(
5–8
), pp.
869
879
.
35.
Choi
,
J.-P.
,
Shin
,
G.-H.
,
Brochu
,
M.
,
Kim
,
Y.-J.
,
Yang
,
S.-S.
,
Kim
,
K.-T.
,
Yang
,
D.-Y.
,
Lee
,
C.-W.
, and
Yu
,
J.-H.
,
2016
, “
Densification Behavior of 316L Stainless Steel Parts Fabricated by Selective Laser Melting byVariation in Laser Energy Density
,”
Mater. Trans.
,
57
(
11
), pp.
1952
1959
. http://dx./doi.org/10.2320/matertrans.M2016284
36.
Liverani
,
E.
,
Toschi
,
S.
,
Ceschini
,
L.
, and
Fortunato
,
A.
,
2017
, “
Effect of Selective Laser Melting (SLM) Process Parameters on Microstructure and Mechanical Properties of 316L Austenitic Stainless Steel
,”
J. Mater. Process. Technol.
,
249
, pp.
255
263
.
37.
Yakout
,
M.
,
Elbestawi
,
M. A.
, and
Veldhuis
,
S. C.
,
2018
, “
On the Characterization of Stainless Steel 316L Parts Produced by Selective Laser Melting
,”
Int. J. Adv. Manuf. Technol.
,
95
(
5
), pp.
1953
1974
.
38.
King
,
W. E.
,
Barth
,
H. D.
,
Castillo
,
V. M.
,
Gallegos
,
G. F.
,
Gibbs
,
J. W.
,
Hahn
,
D. E.
,
Kamath
,
C.
, and
Rubenchik
,
A. M.
,
2014
, “
Observation of Keyhole-Mode Laser Melting in Laser Powder-Bed Fusion Additive Manufacturing
,”
J. Mater. Process. Technol.
,
214
(
12
), pp.
2915
2925
.
39.
Pham
,
M.-S.
,
Dovgyy
,
B.
,
Hooper
,
P. A.
,
Gourlay
,
C. M.
, and
Piglione
,
A.
,
2020
, “
The Role of Side-Branching in Microstructure Development in Laser Powder-Bed Fusion
,”
Nat. Commun.
,
11
(
1
), pp.
1
12
.
40.
ASTM International
,
2013
,
ASTM E112-13: Standard Test Methods for Determining Average Grain Size
,
ASTM International
,
West Conshohocken, PA
, pp.
1
28
.
41.
Kluczyński
,
J.
,
Śnieżek
,
L.
,
Grzelak
,
K.
, and
Mierzyński
,
J.
,
2018
, “
The Influence of Exposure Energy Density on Porosity and Microhardness of the SLM Additive Manufactured Elements
,”
Materials
,
11
(
11
), p.
2304
.
42.
Vander Voort
,
G. F.
,
Lampman
,
S. R.
,
Sanders
,
B. R.
,
Anton
,
G. J.
,
Polakowski
,
C.
,
Kinson
,
J.
,
Muldoon
,
K.
,
Henry
,
S. D.
, and
Scott
,
W. W.
, Jr.
,
2004
,
ASM Handbook, Metallography and Microstructures
,
ASM International
,
Materials Park, OH
.
43.
Krauss
,
G.
,
2015
,
Steels: Processing, Structure, and Performance
,
ASM International
,
Materials Park, OH
.
44.
Zhang
,
S. Y.
,
Compagnon
,
E.
,
Godin
,
B.
, and
Korsunsky
,
A. M.
,
2015
, “
Investigation of Martensite Transformation in 316L Stainless Steel
,”
Mater. Today: Proc.
,
2
, pp.
251
260
.
45.
Krauss
,
G.
, and
Marder
,
A.
,
1971
, “
The Morphology of Martensite in Iron Alloys
,”
Metall. Trans.
,
2
(
9
), pp.
2343
2357
You do not currently have access to this content.