COMPARATIVE ANALYSIS OF PRECIPITATION HARDENING MECHANISMS IN SEMI-AUSTENITIC AND MARTENSITIC STAINLESS STEELS: MICROSTRUCTURE, HEAT TREATMENT, AND MECHANICAL PERFORMANCE
Abstract
Precipitation hardening stainless steels 17-7PH (semi-austenitic) and 17-4PH (martensitic) were compared under controlled heat treatments using hardness and tensile testing, optical/SEM microscopy, and X-ray diffraction. 17-7PH requires a multi-step route; austenite conditioning → martensitic transformation → aging—that culminates in a tempered martensitic matrix strengthened by NiAl intermetallics, achieving UTS ≈ 1510 ± 10 MPa with 469 ± 9 HV and 13 ± 1% elongation. In contrast, 17-4PH reaches peak properties via direct aging of its martensitic solution-annealed structure, with Cu-rich nano-precipitates delivering UTS ≈ 1660 ± 1 MPa, 493.0 ± 4.0 HV, and 9.8 ± 1% elongation. The results highlight distinct precipitation pathways and processing complexity versus performance trade-offs, while micrographs show clean, undecorated grain boundaries in all aged states, indicating intragranular precipitation-controlled strengthening.
Keywords
Precipitation Hardening Stainless Steels Heat Treatment 17-4PH 17-7PH Microstructure–Property Relationship Martensitic Transformation Semi-Austenitic Stainless Steel Martensitic Stainless Steel.
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Details
| Primary Language | English |
|---|---|
| Subjects | Material Characterization |
| Journal Section | Research Article |
| Authors | |
| Submission Date | November 10, 2025 |
| Acceptance Date | December 29, 2025 |
| Publication Date | December 31, 2025 |
| Published in Issue | Year 2025 Volume: 8 Issue: 2 |
