In-Situ Observation of Microcracking in a Tial-Cr-V Alloy Under Compressive Stress

1994 ◽  
Vol 364 ◽  
Author(s):  
Z. J. Pu ◽  
Y. Q. Liu ◽  
K. H. Wu
Keyword(s):  
Grain Boundaries ◽  
Compressive Stress ◽  
Lamellar Microstructure ◽  
Compressive Deformation ◽  
In Situ Observation ◽  
Duplex Structure ◽  
Entire Process ◽  
Fully Lamellar ◽  
Electronic Microscope

AbstractThe entire process of microcrack nucleation in a TiAl-Cr-V alloy with different microstructures is observed in situ by a scanning electronic microscope (SEM) during compressive deformation. The main results are summarized as follows: (1) In the fully lamellar microstructure, the microcracks nucleate mainly at the lamellar grain boundaries between soft-orientation and hard-orientation grains. (2) In the Widmanstatten structure, the microcracks distribute mainly at the intersection between two Widmanstatten plates. (3) In the duplex structure, the microcracks form at the lamella/ lamella and lamella/gamma boundaries. (4) In the nearly gamma structure, microcracks nucleate at gamma/gamma grain boundaries.

In situ observation of interaction between grain boundaries during directional solidification of Si

2018 ◽  
Vol 148 ◽  
pp. 37-41 ◽  
Author(s):  
Lu-Chung Chuang ◽  
Kensaku Maeda ◽  
Haruhiko Morito ◽  
Keiji Shiga ◽  
Wolfram Miller ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Directional Solidification ◽  
In Situ Observation

Local Strain Imaging during Mechanical Loading of Lamellar Microstructures in Titanium Based Alloys

2004 ◽  
Vol 1-2 ◽  
pp. 159-164
Author(s):  
L. Babout ◽  
J. Quinta Da Fonseca ◽  
Michael Preuss
Keyword(s):  
Tensile Testing ◽  
Lamellar Microstructure ◽  
Local Strain ◽  
Boundary Region ◽  
Electron Back Scatter Diffraction ◽  
Surface Strain ◽  
Image Correlation ◽  
Fully Lamellar ◽  
Optical Micrographs

In this work optical microscopy in situ tensile testing has been carried out to study the localisation of surface strain in fully lamellar titanium alloys. The localised strain was measured by analysing the recorded optical micrographs using image correlation, and the orientation of the a lamellae colony was determined by using Electron Back Scatter Diffraction (EBSD). The results show a localisation of strain, which seems to depend on the crystallographic orientation of the a lamellae colony in the lamellar microstructure. No significant strain was observed in the former b grain boundary region.

In Situ Observation of Melting and Solidification

1999 ◽  
Vol 589 ◽  
Author(s):  
H. Saka ◽  
S. Arai ◽  
S. Muto ◽  
H. Miyai ◽  
S. Tsukimoto
Keyword(s):  
Electron Microscope ◽  
Grain Boundaries ◽  
Eutectic Alloy ◽  
Atomic Structure ◽  
In Situ Observation ◽  
Metallic Materials ◽  
Experimental Image ◽  
In Situ Heating ◽  
Melting And Solidification

AbstractMelting and solidification of metallic materials have been observed directly using an in-situ heating experiment in an electron microscope. In pure Al melting initiates at the surface, while in a eutectic alloy melting initiates preferentially at eutectic interfaces and grain boundaries. The atomic structure of a solidliquid interface was identified by comparing an experimental image with computed ones.

In-Situ Observation of Stress in Cu/Pd Multilayers

1995 ◽  
Vol 382 ◽  
Author(s):  
T. Ueda ◽  
G.F. Simenson ◽  
W.D. Nix ◽  
Bruce M. Clemens
Keyword(s):  
Tensile Stress ◽  
Compressive Stress ◽  
In Situ Observation ◽  
Apparent Stress ◽  
Stress Evolution ◽  
Island Growth ◽  
Stress Behavior ◽  
Stress Changes ◽  
Bilayer Period

ABSTRACTStress evolution was studied during growth of Cu/Pd multilayers using an in-situ, laserbased wafer curvature technique which allowed measurement of stress changes associated with sub-monolayer thickness increases. The apparent stress in the Cu layers changes during growth, from compressive, for thickness less than about 0.5 nm, to tensile for thicknesses above this. The stress behavior in the Pd layers depends on the thickness of the underlying Cu layer. Pd deposited on thick (2 nm) Cu layers is under an apparent compressive stress, while Pd deposited on thin (< 1 nm) Cu layers is initially under a tensile stress but changes to a compressive stress at about 0.5 nm. The overall compressive stress maxima observed in multilayers at a bilayer period of 2 nm is explained by this in-situ behavior. The stress behavior in this system is consistent with either island growth of Cu, or thickness dependent alloying behavior, or both.

Effect of Stress and Impurities on Preferential Amorphization on Grain Boundaries in Polycrystalline Silicon

1998 ◽  
Vol 540 ◽  
Author(s):  
Mitsuhiro Takeda ◽  
Somei Ohnuki ◽  
Seiichi Watanabe ◽  
Hiroaki Abe ◽  
Hiroshi Naramoto ◽  
...  
Keyword(s):  
Growth Rate ◽  
Grain Boundaries ◽  
Ion Irradiation ◽  
In Situ Observation ◽  
Constant Growth Rate ◽  
Second Stage ◽  
Critical Dose ◽  
Increasing Temperature ◽  
Constant Growth

AbstractClarifying the local amorphization on the grain boundaries, the in-situ observation during ion-irradiation was carried out for poly-crystalline Si film. The critical dose of amorphous formation increased exponentially with increasing temperature, where the local amorphization was developed at middle temperature. The critical dose was affected by the doped impurity and the grain size. The preferential amorphization on and near grain boundaries had two processes; first stage with rapid growth rate and second stage with almost constant growth rate. The importance of stress was demonstrated from the acceleration due to the stress on the first stage of amorphization.

High Resolution Electron Microscopy In Situ Observation of Dynamic Behavior of Grain Boundaries and Interfaces at Very High Temperatures

1997 ◽  
Vol 3 (5) ◽  
pp. 393-408 ◽  
Author(s):  
T. Kamino ◽  
K. Sasaki ◽  
H. Saka
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Grain Boundaries ◽  
Dynamic Behavior ◽  
High Temperatures ◽  
High Resolution Electron Microscopy ◽  
In Situ Observation ◽  
Resolution Electron ◽  
Very High

High Resolution Electron Microscopy In Situ Observation of Dynamic Behavior of Grain Boundaries and Interfaces at Very High Temperatures

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