Effect of crystallographic texture on the cleavage fracture mechanism and effective grain size of ferritic steel

2014 ◽  
Vol 81 ◽  
pp. 8-11 ◽  
Author(s):  
A. Ghosh ◽  
S. Kundu ◽  
D. Chakrabarti
Keyword(s):  
Grain Size ◽  
Cleavage Fracture ◽  
Crystallographic Texture ◽  
Fracture Mechanism ◽  
Ferritic Steel ◽  
Effective Grain Size

EBSD Analysis of Friction Stir Welded 7136-T76 Aluminum Alloy

2013 ◽  
Vol 203-204 ◽  
pp. 258-261 ◽  
Author(s):  
Izabela Kalemba ◽  
Krzysztof Muszka ◽  
Mirosław Wróbel ◽  
Stanislaw Dymek ◽  
Carter Hamilton
Keyword(s):  
Grain Size ◽  
Aluminum Alloy ◽  
Grain Boundaries ◽  
Texture Analysis ◽  
Crystallographic Texture ◽  
High Frequency ◽  
The Other ◽  
Ebsd Analysis ◽  
High Angle ◽  
Friction Stir

This research addresses the EBSD analysis of friction stir welded 7136-T76 aluminum alloy. The objectives of this study were to evaluate the grain size and their shape, character of grain boundaries in the stirred and thermo-mechanically affected zones, both on the advancing and retreating side as well as to investigate changes in the crystallographic texture. Results of texture analysis indicate the complexity of the FSW process. The texture gradually weakens on moving from the thermo-mechanically affected zone toward the weld center. The stirred zone is characterized by very weak texture and is dominated by high angle boundaries. On the other hand, the thermo-mechanically affected zone exhibits a high frequency of low angle boundaries.

scholarly journals The Effect of Lath Martensite Microstructures on the Strength of Medium-Carbon Low-Alloy Steel

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 232 ◽  
Author(s):  
Chen Sun ◽  
Paixian Fu ◽  
Hongwei Liu ◽  
Hanghang Liu ◽  
Ningyu Du ◽  
...  
Keyword(s):  
Grain Size ◽  
Carbon Content ◽  
Lath Martensite ◽  
Block Size ◽  
Martensitic Steels ◽  
Austenite Grain Size ◽  
Medium Carbon ◽  
Transmission Electron ◽  
Lath Width ◽  
Effective Grain Size

Different austenitizing temperatures were used to obtain medium-carbon low-alloy (MCLA) martensitic steels with different lath martensite microstructures. The hierarchical microstructures of lath martensite were investigated by optical microscopy (OM), electron backscattering diffraction (EBSD), and transmission electron microscopy (TEM). The results show that with increasing the austenitizing temperature, the prior austenite grain size and block size increased, while the lath width decreased. Further, the yield strength and tensile strength increased due to the enhancement of the grain boundary strengthening. The fitting results reveal that only the relationship between lath width and strength followed the Hall–Petch formula of. Hence, we propose that lath width acts as the effective grain size (EGS) of strength in MCLA steel. In addition, the carbon content had a significant effect on the EGS of martensitic strength. In steels with lower carbon content, block size acted as the EGS, while, in steels with higher carbon content, the EGS changed to lath width. The effect of the Cottrell atmosphere around boundaries may be responsible for this change.

Dissipation Pattern of Excess Pore Pressure After Liquefaction in Saturated Sand Deposits

2003 ◽  
Vol 1821 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Ik Soo Ha ◽  
Young Ho Park ◽  
Myoung Mo Kim
Keyword(s):  
Grain Size ◽  
Pore Pressure ◽  
Dynamic Loading ◽  
Time History ◽  
Excess Pore Pressure ◽  
Pore Pressures ◽  
Dissipation Pattern ◽  
Effective Grain Size ◽  
Coefficient Of Uniformity ◽  
Excess Pore

In liquefied areas, the amount of damage to a structure is mainly affected by the postliquefaction behavior of the liquefied ground. Understanding postliquefaction behavior requires understanding the dissipation pattern of excess pore pressure after liquefaction. It is difficult to measure pore pressures generated and dissipated during an earthquake because of the more-or-less randomness of earthquake events. Researchers have artificially generated liquefaction with sand samples in the laboratory and have simulated curves for the time history dissipation of excess pore pressure. To estimate variation in permeability during dynamic loading, which should be known for settlement predictions of the ground undergoing liquefaction, 1-g shaking table tests were carried out on five kinds of sands, all with high liquefaction potentials. During tests, excess pore pressures at various depths and surface settlements were measured. The measured curve of the excess pore pressure dissipation was simulated using the solidification theory. From analysis of the velocity of dissipation, the dissipation pattern of excess pore pressure after liquefaction was examined. Permeability during dissipation was calculated using the measured settlement and dissipation velocity, also used for estimating permeability during dynamic loading. The dissipation velocity of excess pore pressure after liquefaction had a linear correlation with the effective grain size divided by the coefficient of uniformity. The increase in the ground’s initial relative density played a role in shifting this correlation curve toward increased dissipation velocity. Permeability during liquefaction increased 1.4 to 5 times compared with the permeability of the original ground, the increase becoming greater as the effective grain size of the test sand increased and the coefficient of uniformity decreased.

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