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Title: On the role of strain rate, size and notch acuity on toughness: A comparison of two martensitic stainless steels

Conference ·
OSTI ID:524832
; ; ; ;  [1]
  1. Univ. of California, Santa Barbara, CA (United States). Dept. of Mechanical Engineering

The demonstrated swelling resistance and high heat flux capacity make tempered martensitic (TM) steels a leading candidate alloy class for application to fusion reactor first wall and blanket structures. Here, the fracture resistance and micromechanisms of two tempered martensitic steels were characterized over a range of temperatures by both mechanical testing and quantitative fractography. HT-9 and F-82H undergo a fracture mode transition from quasicleavage at low temperature to microvoid coalescence at high temperature. The transition in HT-9 is rather gradual, and the transition in F-82H is extremely abrupt. While the toughness of F-82H was higher in all cases, differences between the two steels depended on test type, strain rate and temperature. The results not only demonstrate the inherent non-uniqueness of the so called ductile-to-brittle transition temperature (DBTT), but also call into question the use of Charpy data for ranking the relative performance of various alloys. The similarities in quasi-cleavage fracture and differences in ductile fracture are manifested in the fracture surfaces and are interpreted in terms of the underlying mechanisms and microstructures.

Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
FG03-87ER52143
OSTI ID:
524832
Report Number(s):
CONF-940657-; TRN: 97:016814
Resource Relation:
Conference: 17. symposium on effects of radiation on materials, Sun Valley, ID (United States), 20-23 Jun 1994; Other Information: PBD: 1996; Related Information: Is Part Of Effects of radiation on materials: 17. international symposium; Gelles, D.S. [ed.] [Pacific Northwest National Lab., Richland, WA (United States)]; Nanstad, R.K. [ed.] [Oak Ridge National Lab., TN (United States)]; Kumar, A.S. [ed.] [Univ. of Missouri, Rolla, MO (United States)]; Little, E.A. [ed.] [University College of Swansea (United Kingdom)]; PB: [1175] p.; ASTM special technical publication, 1270
Country of Publication:
United States
Language:
English