Investigating the effects of hot isostatic pressing and proton irradiation on L-PBF stainless steels via nanoindentation across different strain rates

The performance of additively manufactured (AM) 17-4 PH stainless steel in extreme environments, such as nuclear reactors, relies on its mechanical properties and microstructural stability. Post-processing treatments are crucial for reducing defects and porosity while enhancing mechanical performanc...

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Main Authors: Lutfun Nipa, Hector R. Siller, Mohin Sharma, Bibhudutta Rout, Reza A Mirshams
Format: Article
Language:English
Published: Elsevier 2025-09-01
Series:Results in Engineering
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Online Access:http://www.sciencedirect.com/science/article/pii/S2590123025027045
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author Lutfun Nipa
Hector R. Siller
Mohin Sharma
Bibhudutta Rout
Reza A Mirshams
author_facet Lutfun Nipa
Hector R. Siller
Mohin Sharma
Bibhudutta Rout
Reza A Mirshams
author_sort Lutfun Nipa
collection DOAJ
description The performance of additively manufactured (AM) 17-4 PH stainless steel in extreme environments, such as nuclear reactors, relies on its mechanical properties and microstructural stability. Post-processing treatments are crucial for reducing defects and porosity while enhancing mechanical performance. This study systematically investigates the effects of Hot Isostatic Pressing (HIP) and simulated conditions via proton irradiation (IR) on microstructural and mechanical behavior. HIP effectively decreases porosity, refines grain morphology, and enhances phase stability, leading to a 31 % increase in hardness and a 52 % rise in modulus compared to as printed (AP) samples. At the same time, irradiation creates possible defects that impact dislocation interactions, contributing to strain hardening in AP samples due to the combined effects of inherent microstructural heterogeneity and irradiation-induced defects. An observational evaluation was performed using EBSD analysis for grain structure characterization and nanoindentation to measure hardness, modulus, and strain rate sensitivity (SRS). Individual models were developed to represent the material's behavior in each state, capturing microstructural differences and the impacts of irradiation-induced hardening to clarify the dependency and sensitivity of mechanical properties under varying strain rates. HIP-treated samples demonstrate the most consistent mechanical behavior with improved SRS, attributed to the homogenization of microstructural features. The effect of irradiation on HIP samples indicates that the balance between defect annihilation and irradiation-induced hardening significantly affects mechanical performance, resulting in distinct strain rate-dependent deformation behavior. However, the overall effect is less pronounced than in HIP-only treatments.
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spelling doaj-art-40dbd48e66e84caeb2c843a8c6fc6adb2025-08-20T03:05:49ZengElsevierResults in Engineering2590-12302025-09-012710663710.1016/j.rineng.2025.106637Investigating the effects of hot isostatic pressing and proton irradiation on L-PBF stainless steels via nanoindentation across different strain ratesLutfun Nipa0Hector R. Siller1Mohin Sharma2Bibhudutta Rout3Reza A Mirshams4Department of Mechanical Engineering, University of North Texas, Denton, TX, United StatesDepartment of Mechanical Engineering, University of North Texas, Denton, TX, United States; Corresponding author.Department of Physics, University of North Texas, Denton, TX, United StatesDepartment of Physics, University of North Texas, Denton, TX, United StatesDepartment of Mechanical Engineering, University of North Texas, Denton, TX, United StatesThe performance of additively manufactured (AM) 17-4 PH stainless steel in extreme environments, such as nuclear reactors, relies on its mechanical properties and microstructural stability. Post-processing treatments are crucial for reducing defects and porosity while enhancing mechanical performance. This study systematically investigates the effects of Hot Isostatic Pressing (HIP) and simulated conditions via proton irradiation (IR) on microstructural and mechanical behavior. HIP effectively decreases porosity, refines grain morphology, and enhances phase stability, leading to a 31 % increase in hardness and a 52 % rise in modulus compared to as printed (AP) samples. At the same time, irradiation creates possible defects that impact dislocation interactions, contributing to strain hardening in AP samples due to the combined effects of inherent microstructural heterogeneity and irradiation-induced defects. An observational evaluation was performed using EBSD analysis for grain structure characterization and nanoindentation to measure hardness, modulus, and strain rate sensitivity (SRS). Individual models were developed to represent the material's behavior in each state, capturing microstructural differences and the impacts of irradiation-induced hardening to clarify the dependency and sensitivity of mechanical properties under varying strain rates. HIP-treated samples demonstrate the most consistent mechanical behavior with improved SRS, attributed to the homogenization of microstructural features. The effect of irradiation on HIP samples indicates that the balance between defect annihilation and irradiation-induced hardening significantly affects mechanical performance, resulting in distinct strain rate-dependent deformation behavior. However, the overall effect is less pronounced than in HIP-only treatments.http://www.sciencedirect.com/science/article/pii/S2590123025027045L-PBF17-4 PH SSHIPProton irradiationNanoindentationStrain rate sensitivity
spellingShingle Lutfun Nipa
Hector R. Siller
Mohin Sharma
Bibhudutta Rout
Reza A Mirshams
Investigating the effects of hot isostatic pressing and proton irradiation on L-PBF stainless steels via nanoindentation across different strain rates
Results in Engineering
L-PBF
17-4 PH SS
HIP
Proton irradiation
Nanoindentation
Strain rate sensitivity
title Investigating the effects of hot isostatic pressing and proton irradiation on L-PBF stainless steels via nanoindentation across different strain rates
title_full Investigating the effects of hot isostatic pressing and proton irradiation on L-PBF stainless steels via nanoindentation across different strain rates
title_fullStr Investigating the effects of hot isostatic pressing and proton irradiation on L-PBF stainless steels via nanoindentation across different strain rates
title_full_unstemmed Investigating the effects of hot isostatic pressing and proton irradiation on L-PBF stainless steels via nanoindentation across different strain rates
title_short Investigating the effects of hot isostatic pressing and proton irradiation on L-PBF stainless steels via nanoindentation across different strain rates
title_sort investigating the effects of hot isostatic pressing and proton irradiation on l pbf stainless steels via nanoindentation across different strain rates
topic L-PBF
17-4 PH SS
HIP
Proton irradiation
Nanoindentation
Strain rate sensitivity
url http://www.sciencedirect.com/science/article/pii/S2590123025027045
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