Low absorbed energy ductile dimple fracture in lower shelf region in an ultrafine grained ferrite/cementite steel

2006 ◽  
Vol 37 (9) ◽  
pp. 2897-2900 ◽  
Author(s):  
Ming-Chun Zhao ◽  
Toshihiro Hanamura ◽  
Hai Qiu ◽  
Fuxing Yin ◽  
Kotobu Nagai ◽  
...  
Keyword(s):  
Absorbed Energy ◽  
Ductile Dimple ◽  
Dimple Fracture ◽  
Ultrafine Grained ◽  
Shelf Region

Fracture Behaviour of Fe3Al and FeAl Type Iron Aluminides

2007 ◽  
Vol 567-568 ◽  
pp. 349-352 ◽  
Author(s):  
Andrea Kubošová ◽  
Miroslav Karlík ◽  
Petr Haušild ◽  
J. Prahl
Keyword(s):  
Fracture Toughness ◽  
Cleavage Fracture ◽  
Fracture Behaviour ◽  
Tensile Tests ◽  
Potential Method ◽  
Fractographic Analysis ◽  
Intermetallic Alloys ◽  
Transgranular Cleavage ◽  
Ductile Dimple ◽  
Dimple Fracture

Fracture behaviour of two intermetallic alloys based on FeAl and Fe3Al was studied. On the alloys Fe-40Al-1C (at%) and Fe-29.5Al-2.3Cr-0.63Zr-0.2C (at%) (FA06Z), a basic characterization, the fracture toughness tests and fractographic analysis were carried out. Tensile tests and fracture toughness tests were performed at 20, 200, 400 and 600°C. The fracture toughness values range from 26 MPa.m1/2 at 20°C to 42 MPa.m1/2 at 400°C. In addition, Jintegral dependence on a obtained by potential method was measured. The fractographic analysis showed that samples fractured at 20, 200 and 400°C in the tensile or fracture toughness tests exhibit transgranular cleavage fracture, while at 600°C the ductile dimple fracture predominates.

Fracture Processes in Fully Crystallized Co84Nb10B6 Metallic Glass

1985 ◽  
Vol 58 ◽  
Author(s):  
Janez Megusar ◽  
Tina Vargas ◽  
Nicholas J. Grant
Keyword(s):  
Grain Size ◽  
Fracture Surface ◽  
Fracture Process ◽  
Mean Free Path ◽  
Ductile Dimple ◽  
Fine Grained ◽  
Dimple Fracture ◽  
Mean Grain Size ◽  
The Mean ◽  
Fracture Processes

ABSTRACTFracture processes have been studied in a fully crystallized Co84Nb10B6 glass, with the mean grain size ranging from 43 nm to 0.65 μm. Tensile tested specimens with a mean grain size≥ 0.3 μm showed a ductile (dimple) fracture with microvoids initiated at the boride-cobalt matrix interfaces. As the mean grain size (more correctly, the corresponding mean free path of the deforming cobalt phase) was ≤ 0.1 μm, the fracture process may be similarly initiated by the microvoid formation at the boride-cobalt interface. However, one-to-one correspondence between dimples and boride particles may not be preserved. As a result, dimples become more shallow and may include several boride particles instead. Although the fracture surface of the brittle fine grained Co84Nb10B6 alloy gives an appearance of a cleavage fracture on a macroscale, it is distinctly different, by allowing for the microvoid formation on a microscale.

Development of Prediction Equations on Charpy Upper Shelf Energy for Japanese RPV Steels

2003 ◽  
Author(s):  
Kazunobu Sakamoto ◽  
Takatoshi Hirota ◽  
Toru Osaki ◽  
Minoru Tomimatsu
Keyword(s):  
Regression Analyses ◽  
Prediction Equations ◽  
Shelf Energy ◽  
Absorbed Energy ◽  
Integrity Assessment ◽  
Ductile Brittle Transition Temperature ◽  
Test Reactor ◽  
Charpy Absorbed Energy ◽  
Shelf Region ◽  
Reactor Pressure

It is well known that as the embrittlement due to neutron irradiation on reactor pressure vessel (RPV) steels, there is the tendency of the reduction of Charpy absorbed energy at upper shelf region (USE), in addition to the shift of ductile-brittle transition temperature. Concerning to the regulation of the upper shelf region, no method is provided to evaluate integrity for RPV steels with USE of less than 68J in Japanese codes. Under the circumstance, the reduction tendency of USE using simulated Japanese RPV steels, irradiated by fast neutron up to 1024n/m2 in OECD Halden test reactor, was investigated to establish the basis of the USE prediction after 60 years plant operation for the integrity assessment of the RPVs. The USE prediction equations have been developed through the regression analyses of the test reactor data combined with Japanese surveillance test data. This research was entrusted by the Ministry of Economy, Trade and Industry in Japan.

Charpy absorbed energy of ultrafine-grained Ti-6Al-4V alloy at cryogenic and elevated temperatures

2019 ◽  
Vol 743 ◽  
pp. 581-589 ◽  
Author(s):  
I.P. Semenova ◽  
Ju. Modina ◽  
A.V. Polyakov ◽  
G.V. Klevtsov ◽  
N.A. Klevtsova ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Absorbed Energy ◽  
Ultrafine Grained ◽  
Charpy Absorbed Energy

Characterization of radioiodine therapy failures in Graves’ disease

2001 ◽  
Vol 40 (01) ◽  
pp. 1-6 ◽  
Author(s):  
M. Zimny ◽  
M. Schreckenberger ◽  
P. Reinartz ◽  
B. Nowak ◽  
E. Ostwald ◽  
...  
Keyword(s):  
Radioiodine Therapy ◽  
Thyroid Volume ◽  
Absorbed Dose ◽  
Stepwise Logistic Regression ◽  
Graves Disease ◽  
Significant Variable ◽  
Absorbed Energy ◽  
Volume Function ◽  
Energy Dose

Summary Aim of this study was a characterization of radioiodine therapy (RIT) failures in Graves’ disease without simultaneous Carbimazole. Method: 226 patients with a confirmed diagnosis of Graves’ disease received 686.8 ± 376.4 MBq of iodine-131 orally for thyroid ablation. Target dose was 250 Gy. All patients were followed up for 6 months. Therapy failures were compared with successes regarding possible influencing variables initial thyroid volume, thyroid function, immune activity (TRAb), 1-131 uptake, effective half-life, absorbed energy dose, age and gender. Results: 212 of 226 patients (93.8%) were treated successfully, 14 (6.2%) showed a hyperthyroidism relapse within 6 months which required a second radioiodine therapy. A success rate of 92.5% (62/67) could also be achieved with 67 patients who were hyperthyroid at the time of RIT. Compared to the therapy successes, the 14 failures achieved significantly lower absorbed doses (223.8 ±76.6 Gyvs. 285.2 ±82.1 Gy, ρ <0.005), but with no significant differences regarding age, thyroid volume, function or TRAb (all ρ >0.2). Of the 14 failures, η = 8 reached an absorbed dose <200 Gy and η = 1 a dose <250 Gy, although 5 of the failures reached an absorbed dose of >250 Gy. Stepwise logistic regression revealed only absorbed energy dose as a variable significantly influencing therapy success (p <0.005), but no influence of initial thyroid volume, function, TRAb value, age (all ρ >0.2) or gender (p = 0.13). Two-tailed Fisher’s exact test showed no significant influence of gender on success rates (failures/successes: male 1 /36, female 13/176, ρ = 0.48). Conclusions: Except for the absorbed energy dose, no other significant variable influencing the outcome of radioiodine therapy in Graves’ disease without simultaneous Carbimazole could be found. It should be noted, though, that 5 therapy failures (2.2%) reached an absorbed energy dose of >250 Gy.

Graded Microstructure and Texture in Ultrafine Grained Multi-Layered Immiscible Bimetallic System

2020 ◽  
Author(s):  
K. Dash ◽  
K. Chattopadhyay ◽  
K.U. Yazar ◽  
Satyam Suwas
Keyword(s):  
Ultrafine Grained ◽  
Bimetallic System

Segregation and Precipitation Stabilizing an Ultrafine Grained Al-0.3%Cu Alloy

2020 ◽  
Author(s):  
Linfei Shuai ◽  
Tianlin Huang ◽  
Tianbo Yu ◽  
Guilin Wu ◽  
Niels Hansen ◽  
...  
Keyword(s):  
Cu Alloy ◽  
Ultrafine Grained
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