Zenji Nishiyama

Transmission Electron Microscope Study of the Structure of High Temperature Beta Phase in Cu-Sn Alloy

The structure of beta-phase in Cu-Sn alloy has been studied by electron diffraction using an electron microscope equipped with a high temperature stage. From the superlattice spots it was confirmed that the beta-phase at the high temperature has a Fe3A1 type superlattice. Its diffraction pattern shows strong diffuse streaks which indicate the existence of low frequency transverse lattice vibrations of polarization perpendicular to directions.

Direct Observation of Lattice Defects in Cold-worked High Manganese Steels by Means of Electron Microscopy

Thin foils have been made by electrolytic polishing from bulk specimens of cold-worked high manganese steel. They have been observed by electron microscopy with the object of studying lattice defects formed by cold-working. From the micrographs and the selected area electron diffraction patterns obtained it is concluded that on {111} planes of the austenite matrix very thin (<100A) plates of a hexagonal close-packed phase ( e ) are formed, which correspond to the origins of strain markings formerly found on the etched surface by using the replica, and that ordinary stacking faults as found in 18–8 stainless steels are also present.

Dislocation Images in Pure Iron Observed by Transmission Electron Microscopy

The dislocation image has a line or dotted feature, which depends essentially upon the reflecting condition. This dependency has been clarified the dark field image method and also the method of small variation of the incident angle of electron beam, as follows:– Line images of dislocations: 1) Generally the contrast of dislocation image near an extinction contour is mainly due to the reflection of the same index as that of the contour. 2) The dislocation image, usually appears as a single line, sometimes as a double image, when it is due to one reflection. 3) On the contrary, sometimes the image looks like a single line even when it is due to multiple reflections. 4) The image having black contrast is generally accompanied white side-lines, and when the latter predominates, the image is observed as a white dislocation image. 5) Near the intersection of dislocations of two families, there are found some variations in the image features, which may be not only due to the interaction between strain fields of...

Observations of Dislocation Networks in an Alloy of Body-Centered Cubic Lattice by Electron Microscopy

Electron microscopic observations were made on dislocation networks in thin foils of 55%Cr–Fe alloy annealed at 720°C after cold working. Dislocation cross-grids, hexagonal networks and networks of irregular shape are observed. From the presence of three-fold nodes, it is suggested that Burgers vectors of type [100] may be stable as well as those of type \(\frac{1}{2}\)[111].

A new X-Ray Tube with a Rotating Target

A new powerful X-ray tube has been devised. It has a rotating target cooled with water and sealed with mercury. The mercury column is divided into three parts in order to shorten the height of the tube. As the mercury vapour is settled under cover of an oil of small vapour tension, the tube can be operated as a hot cathode one. The tube here described has the following merits: (1) The rotation of the target can be conducted very smoothly and with a comparatively small power. (2) The construction of the tube, especially, that of the water-cooling-device is comparatively simple. (3) The tube has no fragile part, such as the packing, the metallic sliding part, etc. Hence this tube is very useful for the metallographical research of short time exposure, such as the study of the progress of a transformation, the special high temperature camera, etc.