ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03814.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThe weak‐beam method of electron microscopy enables the high resolution capabilities of the electron microscope to be used in the study of lattice defects. In this paper, the principles of the method are outlined and the experimental procedures for obtaining weak‐beam images are discussed. The experimental diffraction conditions necessary for obtaining quantitative results and the limitations of the method are summarized, and applications of the method to various problems in defect studies are revie

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03815.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYDynamical many‐beam calculations were performed for the investigation of the diffraction contrast of small lattice defects observed in the electron microscope under weak‐beam conditions. A new computational method was developed with which the depth positionzoof the defect and the thicknesstof the foil were eliminated from the integration procedure of the differential equations. The contrast figures for dislocation loops which were inclined to the foil plane and for spherical inclusions were calculated for various excitation errors of the weakly excited beam and for various combinations oftandz0.The dependence of the contrast figures onz0(‘depth oscillations’) were studied in detail. The results of the calculations are compared with experimental obser

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03816.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYTheoretical and experimental investigations have been carried out to determine under which conditions weak‐beam images can give useful information on the geometry, size and nature of small Frank loops. Suitable experimental conditions for obtaining such information were deduced from computed weak‐beam images of Frank loops under various selected loop and foil orientations and diffraction vectors. Experiments to check these deductions were performed in silicon damaged by irradiation with phosphorus ions. It was found that the geometry and size of loops of diameter8 nm (80 Å) viewed normal to their habit plane was well defined by weak‐beam images taken in {220} reflections lying in the loop plane for whichg.b= 0 andg.b×u≠ 0. By imaging in reflections withgvectors not in the loop plane the enclosed stacking faults were imaged (thus confirming the loops to be Frank loops) and the sense of the Burgers vector (i.e. the loop nature) was d

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03817.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYWeak‐beam microscopy has been used to examine the dislocation loops formed when ion implanted silicon is annealed in the temperature range 900–1300 K. The extinction distances of about 10 nm, resulting from the use of large deviation parametersS'enable stacking fault fringes of 4nm spacing to be resolved in faulted loops. The projected shape of the dislocation loops and the variable contrast along the perimeter of the bounding partial dislocation enables the habit planes of the dislocation loops to be determined from inspection. These together with the width of the dislocation image, which is about 3 nm enables the type of loop to be characterized completely from a single microgr

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03818.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThe weak‐beam technique of electron microscopy (Cockayne, Ray&Whelan, 1969) has been applied to the examination of dislocations in germanium. These are shown to be dissociated into partial dislocations with a separation in the edge orientation of 5.5 ± 1·0 nm. A value for the stacking‐fault energy of γ = 60 ± 8 mJ m−2(erg cm−2) is deduced from the measured dissociation width as a function of orientation, using anisotropic elasti

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03819.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYA value for the 1/2{110} antiphase boundary (APB) energy in stoichiometric NiAl has been obtained by employing the weak‐beam technique to resolve the separation of the two 1/2partial dislocations composing the<111 superdislocation.A separation of 4·5 nm is obtained corresponding to an APB energy of 200 ± 40 mJ m−2(erg

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03820.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThe advantages of the weak‐beam technique of electron microscopy for the study of small defects and dislocations are illustrated by micrographs taken of small loops in aluminium and Al–Ag alloys, GP zones and θ″ precipitates in Al + 4% Cu, and dislocation networks in Cu + 20% Zn. An estimate of 19·5 mJ m−2(erg cm∼2) is made for the stacking‐fault energy of Cu–20% Zn from the size of extended nodes and the width of the dissociated dislocations imaged under weak

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03821.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThe transmission electron microscope (TEM) weak‐beam method was employed in a study of dislocation nodes both in deformed single crystal Si and at the Ge/(lll)Si interface. All intrinsic nodes were observed to be extended, and measurements of their geometry in Si were used to determine the intrinsic stacking‐fault energy. However, only approximately half of the extrinsic nodes were extended and this was interpreted in terms of an energy barrier to node extens

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03822.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

SUMMARYThe weak‐beam technique of electron microscopy (Cockayne, Ray&Whelan, 1969) has been used to image the four components of super‐lattice dislocations in a range of iron‐aluminium alloys, between 26 and 30 at % aluminium, with D03‐type long‐range order. Values of the first and second nearest neighbour interaction energies have been measured from the observed separations of the c

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1973.tb03823.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY