A nanoindentation study on grain-boundary contributions to strengthening and aging degradation mechanisms in advanced 12 Cr ferritic steel

2007 ◽  
Vol 22 (1) ◽  
pp. 175-185 ◽  
Author(s):  
Jae-il Jang ◽  
Sanghoon Shim ◽  
Shin-ichi Komazaki ◽  
Tetsuya Honda
Keyword(s):  
Grain Boundary ◽  
Ferritic Steel ◽  
Microstructural Analysis ◽  
Thermal Exposure ◽  
Strengthening Effect ◽  
Degradation Mechanisms ◽  
Block Boundary ◽  
Softening Behavior ◽  
Matrix Strength ◽  
Virgin Sample

Nanoindentation experiments and microstructural analysis were performed on advanced 12% Cr ferritic steel having extremely fine and complex martensitic microstructures, to answer unsolved questions on the contributions of grain boundaries to strengthening and aging degradation mechanisms in both as-tempered and thermally aged steels. Interesting features of the experimental results led us to suggest that among several high angle boundaries, block boundary is most effective in enhancing the macroscopic strength in as-tempered virgin sample, and that a decrease in matrix strength rather than reduction in grain-boundary strengthening effect is primarily responsible for the macroscopic softening behavior observed during thermal exposure.

Quantified Relation between Grain Boundary Angle and Interfacial Stability of PWA1484 Superalloy during Thermal Exposure

2019 ◽  
Vol 51 (1) ◽  
pp. 380-389
Author(s):  
Qinjia Wang ◽  
Jinxia Song ◽  
Dinggang Wang ◽  
Chengbo Xiao ◽  
Xidong Hui
Keyword(s):  
Grain Boundary ◽  
Thermal Exposure ◽  
Interfacial Stability

scholarly journals Grain boundary sliding associated with low strain rate at 1000 °C in recrystallized ODS ferritic steel

2016 ◽  
Vol 9 ◽  
pp. 338-341 ◽  
Author(s):  
R. Kamikawa ◽  
S. Ukai ◽  
N. Oono ◽  
T. Kaito ◽  
T. Torimaru ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Strain Rate ◽  
Ferritic Steel ◽  
Grain Boundary Sliding ◽  
Boundary Sliding ◽  
Low Strain Rate

Direct Observation of Two-Dimensional Grain Boundary Sliding and Switching in ODS Ferritic Steel

2016 ◽  
Vol 838-839 ◽  
pp. 43-50
Author(s):  
Eiichi Sato ◽  
Hiroshi Masuda ◽  
Yoshito Sugino ◽  
Shigeharu Ukai
Keyword(s):  
Grain Boundary ◽  
Ferritic Steel ◽  
Tensile Deformation ◽  
Grain Boundary Sliding ◽  
Grain Structure ◽  
Two Dimensional ◽  
Kernel Average Misorientation ◽  
Boundary Sliding ◽  
High Temperature Tensile ◽  
Region Ii

High-temperature tensile deformation was performed using an oxide-dispersionstrengthened (ODS) ferritic steel,, which has grain structure largely elongated and aligned in one direction, in the perpendicular direction. In the superplastic region II, two-dimensional grain boundary sliding (GBS) was achieved, in which the material did not shrink in the grain-axis direction and grain-boundary steps appeared only in the surface perpendicular to the grain axis. In this condition, a classical grain switching event was observed. Using kernel average misorientation maps drawn with SEM/EBSD, dominant deformation mechanisms and accommodation processes for GBS were examined in the different regions. Cooperative grain boundary sliding, in which only some of grain boundaries slide, was also observed.

Interface Reaction and Atomic Transport During COSi2 Film Formation

1992 ◽  
Vol 260 ◽  
Author(s):  
Z. G. Xiao ◽  
J. W. Honeycutt ◽  
G. A. Rozgonyi
Keyword(s):  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Film Formation ◽  
Microstructural Analysis ◽  
Interface Reaction ◽  
Lattice Diffusion ◽  
Atomic Transport ◽  
Transmission Electron ◽  
Boundary Diffusion Coefficient ◽  
Short Annealing

ABSTRACTThe formation process of COSi2 films grown from Co deposited on a Si single crystal was investigated as a function of very short annealing times by transmission electron microscopy and x-ray diffraction. Information on the interfacial reactions and atomic transport phenomena was obtained from a microstructural analysis of the CoxSiy layers formed. It was demonstrated that Co is the dominant diffusion species during COSi2 formation. Co atoms are generated at the COSi2/COSi2 interface via the reaction 2CoSi=CoSi2+Co and diffuse to the COSi2/Si interface, where they react with Si by Co+2Si=CoSi2. Direct microscopic evidence indicates that diffusivity of Co atoms along a COSi2 grain boundary greatly exceeds that through the COSi2 lattice. The grain boundary diffusion coefficient is estimated to be up to 100 times larger than the lattice diffusion coefficient. On this basis the influence of grain size on COSi2 film formation is discussed.

Characterization of grain boundary carbides in ferritic steel and correlation with creep resistance

1983 ◽  
Vol 12 (1-2) ◽  
pp. 110
Author(s):  
A. Benvenuti ◽  
L. Borghi ◽  
G. Chevallard
Keyword(s):  
Grain Boundary ◽  
Creep Resistance ◽  
Ferritic Steel

On the Failure of Intelligent Power Devices Induced by Extreme Electro-Thermal Fatigue. A Microstructural Analysis

2007 ◽  
Vol 131-133 ◽  
pp. 523-528
Author(s):  
Benjamin Khong ◽  
Marc Legros ◽  
Philippe Dupuy ◽  
Colette Levade ◽  
Guy Vanderschaeve
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
Thermal Fatigue ◽  
Heat Sink ◽  
Microstructural Analysis ◽  
Power Devices ◽  
Metallization Layer ◽  
Non Destructive ◽  
Non Destructive Techniques ◽  
Causes Of Failure

Microstructural analysis of power devices were carried out on components from Freescale Semiconductor that underwent extreme electro-thermal fatigue. Several destructive and non destructive techniques were used. It is shown that the main cause of devices failure is delamination between the heat sink and the power die. Additional causes of failure are identified. The fatigue-induced modifications of the structure of the metallization layer (grain growth, grain boundary grooving) is also discussed.

Sign in / Sign up

Export Citation Format

Share Document