Benchmark analyses of probabilistic fracture mechanics for cast stainless steel pipe

Hojo, Kiminobu*; Hayashi, Shotaro*; Nishi, Wataru*; Kamaya, Masayuki*; Katsuyama, Jinya; Masaki, Koichi*; Nagai, Masaki*; Okamoto, Toshiki*; Takada, Yasukazu*; Yoshimura, Shinobu*

Mechanical Engineering Journal (Internet), 3(4), p.16-00083_1 - 16-00083_16, 2016/08

https://doi.org/10.1299/mej.16-00083

Performance demonstration certification of non-destructive inspection for cast stainless steel (CASS) has been planned but the target flaw depth to be detected has not been determined yet in Japan. The target flaw size is closely connected to the allowable flaw size which is determined by flaw evaluation of the rules on fitness-for-service. For rational mitigation of the acceptable flaw size, application of probabilistic fracture mechanics (PFM) is one of the useful countermeasures compared with deterministic approach. In this paper, benchmark problems for a CASS pipe were proposed with intention applying and verifying PFM codes. As the fracture modes, fatigue crack extension, plastic collapse and ductile crack initiation were assumed. Six organizations participated in the benchmark analysis and failure probabilities from them were compared. As a result the failure probability of each problem showed good agreement and the code for application of CASS issue has been verified.

Twin intersection in tensile deformed -TiAl intermetallic compounds

Sawai, Tomotsugu; Hishinuma, Akimichi

Journal of Physics and Chemistry of Solids, 66(2-4), p.335 - 338, 2005/02

https://doi.org/10.1016/j.jpcs.2004.06.059

TiAl intermetallic compounds are potential materials for high temperature structural applications. They have also low induced radio-activity and good radiation resistance, which make these alloys very attractive in nuclear applications. Their ductility at low temperatures should be, however, still improved and their deformation mechanism is of great concern. In this study, intersections of deformation twins in -TiAl grains were examined in Ti-47at%Al alloy specimens tensile-tested at 873 K. Transmission electron microscopy (TEM) revealed 1/2110]{111} ordinary-type dislocations and 1/6112]{111} twins in deformed -TiAl grains. Some -TiAl grains contained twins on two different {111} planes, which intersect along 110] directions (type-1). No twin intersection along 101] (type-2) was observed, which was often reported in compressed specimens. Results are discussed with the Schmid factor distributions of twinning systems and ordinary slip systems as the function of tensile directions.

The Characterization of HIP and RHIP consolidated NiAl intermetallic compounds containing chromium particles

Ishiyama, Shintaro; Buchkremer, H. P.*; Stver, D.*

Nihon Kinzoku Gakkai-Shi, 68(9), p.831 - 837, 2004/09

https://doi.org/10.2320/jinstmet.68.831

NiAl intermetallics with dispersive Cr particles consolidated by the Hot Isostaic Press(HIP) and Reactive HIP(RHIP) techniques, has been investigated. Mechanical properties of HIPed and RHIPed materials with various Cr concentrations ranging form 0 to 30 mass.%Cr, were examined at various temperatures. The consolidation temperature of RHIP materials decreases with Cr addition; when RHIPing NiAl+xCr compounds with 25 mass% has attained, remarkable high ductility over 17% elongation and over 400MPa tensile strength at 873K. A very high tensile strength of HIPed NiAl+20wt.%Cr about 600MPa with 10% elongation was achieved at 873K.

On the effects of fatigue precracking on the microstructure around precrack in 1TCT fracture toughness specimen of F82H-IEA

Tanigawa, Hiroyasu; Hashimoto, Naoyuki*; Sokolov, M. A.*; Klueh, R. L.*; Ando, Masami

Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.58 - 60, 2004/04

1TCT fracture toughness specimens of F82H-IEA steel were fatigue precracked and sliced in specimen thickness wise for microstructure analysis around the precrack. The microstructure around the precrack was observed by optical microscopy (OM), scanning electron microscopy (SEM), orientation imaging microscopy (OIM), and transmission electron microscopy (TEM). TEM samples around the crack front were prepared by focused ion beam (FIB) processor. The fracture surfaces of tested 1TCT specimens were also observed. OM observation showed that the precrack penetration was straight in the beginning, and then tended to follow a prior austenite grain boundary and to branch into 2 to 3 directions at the terminal. SEM and OIM observations revealed that the both microstructures around the precracks and ahead of the precrack had turned into cell structure, which is the typical microstructure of fatigue-loaded F82H. TEM images and inverse pole figures obtained from the crack-front region confirmed this structure change.

Elementaly development for beryllide pebble fabrication by rotating electrode method

Uchida, Munenori*; Kawamura, Hiroshi; Uda, Minoru*; Ito, Yoshio*

Fusion Engineering and Design, 69(1-4), p.491 - 498, 2003/09

https://doi.org/10.1016/S0920-3796(03)00394-6

no abstracts in English

Mechanical property evaluation of stressed microscale zone by indentation technique

Naoe, Takashi*; Futakawa, Masatoshi; Wakui, Takashi*; Kogawa, Hiroyuki

Nihon Kikai Gakkai Kanto Shibu Ibaraki Koenkai (2002) Koen Rombunshu, p.3 - 4, 2002/09

no abstracts in English

Development of PFM code with a function of ductile crack extension analysis, 2; Sensitivity analysis using the ductile crack extension analysis function of PASCAL

Kato, Daisuke*; Li, Y.*; Shibata, Katsuyuki; Onizawa, Kunio

Nihon Kikai Gakkai 2001-Nendo Nenji Taikai Koen Rombunshu, p.391 - 392, 2001/00

no abstracts in English

Application of the distributed database (Data-Free-Way) on the analysis of mechanical properties in neutron irradiated 316 stainless steel

Fujita, Mitsutane*; Kinugawa, Junichi*; Tsuji, Hirokazu; Kaji, Yoshiyuki; Tachi, Yoshiaki*; Saito, Junichi*; Shimura, Kazuki*; Nakajima, Ritsuko*; Iwata, Shuichi*

Fusion Engineering and Design, 51-52, p.769 - 774, 2000/11

https://doi.org/10.1016/S0920-3796(00)00237-4

no abstracts in English

Evaluation of charpy impact property in high strength ferritic/martensitic steel (PNC-FMS)

;

JNC TN9400 2000-035, 164 Pages, 2000/03

JNC-TN9400-2000-035.pdf:3.67MB

High Strength Ferritic/Martensitic Steel (PNC-FMS : 0.12C-11Cr-0,5Mo-2W-0.2V-0.05Nb), developed by JNC, is one of the candidate materials for the long-life core of large-scale fast breeder reactor. Ductile brittle transition temperature (DBTT) was tentatively determined in 1992 in material design base standard of PNC-FMS. Howevcr, specimen size effect on impact property and upper shelf energy (USE) have not been evaluated. ln this study, effects of specimen size, thermal aging and neutron irradiation on the charpy impact property of PNC-FMS were evaluated, using together with recently obtained data. The design value of USE and DBTT as fabricated and each correlation of aging and irradiation effects were determined. The results are summarized as follows. (1)lt was found that USE is related to (Bb) as USE=m(Bb), where B is specimen width, b is ligament size and both m and n are constant. For PNC-FMS, n value is equal to 1.4. It's possible to determine n value from USE (J) for full size specimen using the correlation: n=1.3810 USE + 1.20. (2)lt was clarified that DBTT is correlated with (BKt) as DBTT=p(logBKt)+q, where Kt is elastic stress concentration factor and both p and q are constant. For PNC-FMS, the correlation is as follows: DBTT=119(logBKt)-160. (3)DBTT estimated at the irradiation temperature from 350 to 650 C for sub size specimen (width and height are 3 and 10 mm, respectively), was below 180 C, based on the design value of DBTT as fabricated and each correlation of aging and irradiation effects.

Neutron irradiation embrittlement of polycrystalline and single crystalline molybdenum

Watanabe, Katsutoshi; Hishinuma, Akimichi; *; *

Journal of Nuclear Materials, 258-263, p.848 - 852, 1998/00

https://doi.org/10.1016/S0022-3115(98)00120-2

no abstracts in English