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: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-09-01
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| Series: | Results in Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2590123025027045 |
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| Summary: | 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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| ISSN: | 2590-1230 |