Microhardness anisotropy on the (010) cleavage plane of single crystals of Bi2S3 and Sb2S3

1992 ◽  
Vol 27 (5) ◽  
pp. 1357-1360 ◽  
Author(s):  
Hong Li ◽  
M. Jensen ◽  
R. C. Bradt
1990 ◽  
Vol 213 ◽  
Author(s):  
Kehi-Minn Chang ◽  
R. Darolia ◽  
H.A. Lipsitt

ABSTRACTSingle crystals of B2 aluminides, including FeAl, NiAl, and CoAl, were tested to investigate their fracture behavior. Specimens were aligned along specific orientations of the crystal lattice. Both uniaxial tension and notched bend tests revealed a cleavage fracture in all crystals. The cleavage occurred along a specific crystalline plane: {100} for FeAl; {110} for NiAl and CoAl. A model based on the ordering energy of unlike atoms is proposed to explain the preferred cleavage plane in these B2 structures. Fracture on transient planes around {115} are observed in NiAl before the crack growth continues on a cleavage plane.


1991 ◽  
Vol 185-189 ◽  
pp. 2549-2550 ◽  
Author(s):  
Koji Yamano ◽  
Kazuhiro Shimaoka ◽  
Kazuhiko Takahashi ◽  
Tatsuro Usuki ◽  
Yorinobu Yoshisato ◽  
...  

2005 ◽  
Vol 86 (1) ◽  
pp. 012905 ◽  
Author(s):  
R. Chu ◽  
Z. Xu ◽  
G. Li ◽  
H. Zeng ◽  
H. Yu ◽  
...  

1994 ◽  
Vol 367 ◽  
Author(s):  
V. Glebovsky ◽  
H. Fishmeister ◽  
J. Riedle ◽  
V. Semenov ◽  
P. Gumbsch

AbstractFor fracture studies on oriented W monocrystalline specimens it is necessary to produce very sharp, stopped precracks, which presents difficulties in the case of W. The experimental procedure and technique to produce precracks is described. The fracture experiments gave strong indications for a preference of the {100} plane as cleavage plane. It was found that the {110} planes successfully resist crack propagation, although they are the planes with the lowest surface energy. The appearance of the {121} plane as a cleavage plane in our experiments makes further studies with oriented W monocrystalline samples necessary.


1976 ◽  
Vol 31 (3-4) ◽  
pp. 251-258
Author(s):  
W.-W. Falter

Hole currents are observed by illuminating 2,3 DN single crystals with 347 nm and 337 nm. The probability of generating free holes is a function of temperature and electric field-strength. In the cleavage plane of the crystals the mobility does not depend on the direction of the applied field and amounts to 2.6·10-1 cm2/Vsec at room temperature, which exceeds the related value measured perpendicularly to the plane by a factor of four. The temperature-dependence of the mobility indicates shallow hole-trapping exspecially close to the surface. The trap depth is estimated to be 10-2 eV. Temperature also influences the pulse shape, by which one can conclude that hole traps of 0.2 eV and ≲ 0.1 eV exist in a thin surface layer. Photocurrents exited with 347 nm increase stronger than quadratically with the electric field. Deep hole traps, being also restricted to the surface region of the crystals, are made responsible for this fact.


1990 ◽  
Vol 213 ◽  
Author(s):  
H.R.P. Inoue ◽  
C.M. Wayman ◽  
T. Saburi

ABSTRACTFracture and dislocation structures of single crystals of the L12-type compound Ni3Ge deformed in tension-compression at room temperature are investigated by optical and electron microscopy. After considerable plastic deformation, cracks nucleate along primary (111) planes of [245]-oriented single crystals and grow in zigzag manner by connecting one octahedral plane to another. Fracture occurs by brittle cleavage. Similar cleavage fracture also occurs when thin films (whose plane is (111)) prepared from cyclically deformed specimens are further deformed at room temperature. These observations are different from those reported in a previous study where the cleavage plane is claimed to be {001} for single crystals deformed in tensio at room temperature. A number of piled-up dislocations are emitted due to stress concentration at and ahead of crack tips, evidencing that this compound is intrinsically ductile. Superlattice intrinsic stacking faults are observed in front of crack tips along with a moire structure. Although there is argument that such moire structures are formed in persistent slip bands during cyclic deformation of Ni3Al, this is unlikely in the present case. The moire structure observed is believed to be formed by deformation of the thin (111) film.


1984 ◽  
Vol 21 (4) ◽  
pp. 379-381
Author(s):  
R.C. Shah ◽  
C.F. Desai ◽  
G.R. Pandya ◽  
V.P. Bhatt

2005 ◽  
Vol 54 (2) ◽  
pp. 935
Author(s):  
Chu Rui-Qing ◽  
Xu Zhi-Jun ◽  
Li Guo-Rong ◽  
Zeng Hua-Rong ◽  
Yu Han-Feng ◽  
...  

Author(s):  
Lucien F. Trueb

A new type of synthetic industrial diamond formed by an explosive shock process has been recently developed by the Du Pont Company. This material consists of a mixture of two basically different forms, as shown in Figure 1: relatively flat and compact aggregates of acicular crystallites, and single crystals in the form of irregular polyhedra with straight edges.Figure 2 is a high magnification micrograph typical for the fibrous aggregates; it shows that they are composed of bundles of crystallites 0.05-0.3 μ long and 0.02 μ. wide. The selected area diffraction diagram (insert in Figure 2) consists of a weak polycrystalline ring pattern and a strong texture pattern with arc reflections. The latter results from crystals having preferred orientation, which shows that in a given particle most fibrils have a similar orientation.


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