Microstructural evolution and strengthening of selective laser melted 316L stainless steel processed by high-pressure torsion
Microstructural evolution and strengthening of selective laser melted 316L stainless steel processed by high-pressure torsion
The microstructural evolution and deformation mechanisms of 316L stainless steel fabricated by Selective Laser Melting (SLM) and then processed by high-pressure torsion (HPT) were investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD). TEM observations and XRD line broadening analysis reveal that the deformation in the HPT-processed alloy can be categorised into three deformation stages, related to the microstructural features and the corresponding equivalent strain values, εeq. Twinning, dislocation generation and multiplication, and the formation of twin-matrix lamellae are the main deformation mechanisms in stage 1 (εeq. = ~0–10). Shear banding of the twin-matrix lamellae and formation secondary nanotwins contribute to the deformation process in stage 2 (εeq. = ~10–40), while an equilibrium or saturation stage indicated by the formation of equiaxed nano-sized grains is reached in stage 3 (εeq. > 40). A model based on the linear additive theory was then established to evaluate the contribution of solid solution, dislocation, grain boundary, and twinning to the hardness increase and overall strengthening attained by this alloy.
316L stainless steel, High-pressure torsion, Microstructural evolution, Model, Selective laser melting, Strengthening
1-12
Mohd Yusuf, Shahir Yasin Bin
5888c057-33da-45f3-a84d-95a291db8f34
Chen, Ying
8658c64a-54df-4113-b8af-9bf850dbde46
Yang, Shoufeng
e0018adf-8123-4a54-b8dd-306c10ca48f1
Gao, Nong
9c1370f7-f4a9-4109-8a3a-4089b3baec21
January 2020
Mohd Yusuf, Shahir Yasin Bin
5888c057-33da-45f3-a84d-95a291db8f34
Chen, Ying
8658c64a-54df-4113-b8af-9bf850dbde46
Yang, Shoufeng
e0018adf-8123-4a54-b8dd-306c10ca48f1
Gao, Nong
9c1370f7-f4a9-4109-8a3a-4089b3baec21
Mohd Yusuf, Shahir Yasin Bin, Chen, Ying, Yang, Shoufeng and Gao, Nong
(2020)
Microstructural evolution and strengthening of selective laser melted 316L stainless steel processed by high-pressure torsion.
Materials Characterization, 159, , [110012].
(doi:10.1016/j.matchar.2019.110012).
Abstract
The microstructural evolution and deformation mechanisms of 316L stainless steel fabricated by Selective Laser Melting (SLM) and then processed by high-pressure torsion (HPT) were investigated by optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and x-ray diffraction (XRD). TEM observations and XRD line broadening analysis reveal that the deformation in the HPT-processed alloy can be categorised into three deformation stages, related to the microstructural features and the corresponding equivalent strain values, εeq. Twinning, dislocation generation and multiplication, and the formation of twin-matrix lamellae are the main deformation mechanisms in stage 1 (εeq. = ~0–10). Shear banding of the twin-matrix lamellae and formation secondary nanotwins contribute to the deformation process in stage 2 (εeq. = ~10–40), while an equilibrium or saturation stage indicated by the formation of equiaxed nano-sized grains is reached in stage 3 (εeq. > 40). A model based on the linear additive theory was then established to evaluate the contribution of solid solution, dislocation, grain boundary, and twinning to the hardness increase and overall strengthening attained by this alloy.
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Accepted/In Press date: 11 November 2019
e-pub ahead of print date: 13 November 2019
Published date: January 2020
Additional Information:
Funding Information:
This work was supported by a PhD studentship for S. Mohd Yusuf from Faculty of Engineering and Physical Sciences at the University of Southampton, UK. Y. Chen would like to acknowledge the financial supports from the National Natural Science Foundation of Fujian Province , China (No. 51601162 ) and High-Level Talent Funding for Xiamen Oversea Returnee .
Publisher Copyright:
© 2019
Keywords:
316L stainless steel, High-pressure torsion, Microstructural evolution, Model, Selective laser melting, Strengthening
Identifiers
Local EPrints ID: 436892
URI: http://eprints.soton.ac.uk/id/eprint/436892
ISSN: 1044-5803
PURE UUID: a2d04047-3690-4c03-994b-76f8257c7c98
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Date deposited: 13 Jan 2020 17:33
Last modified: 17 Mar 2024 05:10
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Ying Chen
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