Effect of thermomechanical treatments on the room-temperature mechanical behavior of iron aluminide Fe{sub 3}Al

Journal Article · Tue Oct 01 04:00:00 EDT 1996 · Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science

DOI:https://doi.org/10.1007/BF02663848· OSTI ID:417856

Agarwal, A; Balasubramaniam, R; Bhargava, S ^[1]

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1. Indian Inst. of Tech., Kanpur (India). Dept. of Materials and Metallurgical Engineering

The room-temperature hydrogen embrittlement (HE) problem in iron aluminides has restricted their use as high-temperature structural materials. The role of thermomechanical treatments (TMT), i.e., rolling at 500 C, 800 C, and 1,000 C, and post-TMT heat treatments, i.e., recrystallization at 750 C and ordering at 500 C, in affecting the room-temperature mechanical properties of Fe-25Al intermetallic alloy has been studied from a processing-structure-properties correlation viewpoint. It was found that when this alloy is rolled at higher temperature, it exhibits a higher fracture strength. This has been attributed to find subgrain size (28 {micro}) due to dynamic recrystallization occurring at the higher rolling temperature of 1,000 C. However, when this alloy is rolled at 1,000 C and then recrystallized, it shows the highest ductility but poor fracture strength. This behavior has been ascribed to the partially recrystallized microstructure, which prevents hydrogen ingress through grain boundaries and minimizes hydrogen embrittlement. When the alloy is rolled at 1,000 C and then ordered at 500 C for 100 hours, it shows the highest fracture strength, due to its finer grain size. The alloy rolled at 500 C and then ordered undergoes grain growth. Hence, it exhibits a lower fracture strength of 360 MPa. Fracture morphologies of the alloy were found to be typical of brittle fracture, i.e., cleavage-type fracture in all the cases.

• Sponsoring Organization: USDOE
• OSTI ID: 417856
• Journal Information: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 10 Vol. 27; ISSN MMTAEB; ISSN 1073-5623
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM ALLOYS
CORRELATIONS
ELECTRON MICROPROBE ANALYSIS
FRACTURE PROPERTIES
GRAIN SIZE
HEAT TREATMENTS
HYDROGEN EMBRITTLEMENT
INTERMETALLIC COMPOUNDS
IRON ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
RECRYSTALLIZATION
ROLLING
SAMPLE PREPARATION
TENSILE PROPERTIES
THERMOMECHANICAL TREATMENTS
X-RAY DIFFRACTION