scholarly journals X-ray examination of certain copper-zinc alloys at elevated temperatures

1934 ◽  
Vol 145 (854) ◽  
pp. 258-267 ◽  
Keyword(s):  
Elevated Temperatures ◽  
Close Contact ◽  
Thin Sheet ◽  
Thin Foil ◽  
The Other ◽  
Copper Sheet ◽  
Zinc Alloys ◽  
Β Phase ◽  
Copper Zinc ◽  
Thermo Couple

This investigation is a continuation of the word on copper-zinc alloys reported in previous papers. Our previous measurements were made on quenched alloys, and it was assumed that the conditions prevailing at any temperature at the moment of quenching were retained in the quenched samples. In the present word an attempt is made to investigate the validity of this assumption by examining the alloys at the actual temperatures of annealing. Attention is directed mainly to the β-phase in tire pure region and in the mixed regions on either side of the pure phase. It was hoped that such measurements might also throw more light on the nature of the β-transformation. Apparatus and Method of Experiment . The precision camera was the same in principle as that previously used and described, with modifications in deign for high temperature word. It was made entirely of invar except that three silica rods connected the portion of the drum carrying the film to that carrying the sample. By this device the one part was well insulated thermally from the other. In order to take photographs in vacuo , the camera was fitted into a brass box with a removable lid and water-cooled sides; inside the box, the heater, consisting of "Kanthal" resistance wire embedded in alundum cement, was mounted. To hold the sample, which was in the form of fine filings on thin foil, against the camera frame, a thin sheet of copper foil was used. This was anchored with insulating porcelain beads and wire springs to the camera frame carrying the film. To minimize the heat passing from the sample to the camera frame, a thin sheet of mica of definite thickness was used around the slot over which the sample was placed. The sample was heated by bringing the heater, shaped to the contour of the camera frame, into close contact with a similarly shaped copper sheet about 1⋅5 mm. thick, into which the "hot" junction of one thermo-couple was silver-soldered; this in turn pressed against the foil on which the sample was mounted. Leads for the thermo-couple pyrometers—one to measure the approximate temperature of the sample photographed and the other to measure the camera temperature near tire film—passed through insulated plugs in one side of the box. On the opposite side, leads to the heater were similarly inserted. An outlet for exhausting the box completed the construction.

Evaluation of the entropies of ordered β-Phase copper-zinc alloys

1971 ◽  
Vol 19 (11) ◽  
pp. 1227-1231 ◽  
Author(s):  
R Crombie ◽  
D.B Downie
Keyword(s):  
Zinc Alloys ◽  
Β Phase ◽  
Copper Zinc

Kossel Line Micro-Diffraction Stum on Precipitation of Alpha from Beta in Copper Zinc Alloys

1968 ◽  
Vol 12 ◽  
pp. 174-187
Author(s):  
Gunji Shiwoda ◽  
Kenji Isokawa ◽  
Masataka Umeno
Keyword(s):  
Grain Boundary ◽  
Orientation Relationship ◽  
Electron Microprobe ◽  
Target Point ◽  
Zinc Alloys ◽  
Β Phase ◽  
Vacancy Model ◽  
Kossel Technique ◽  
Copper Zinc ◽  
Quantitative Analyses

AbstractBy the electron microprobe Kossel technique, an a-precipitate at a grain boundary of a Cu-45wt% Zn alloy was found to consist of only one crystal and the orientation relationship between the a precipitate and one of the grains beside the grain boundary was (110)β//(111)α and <111>β//<110>α. This is the same relationship as the case α a precipitates in β-phase grains. A little deviation from the exact coincidence of above orientation relationship was observed. The vacancy model for the production of a denuded zone in the same alloy was confirmed by a line scanning analyses using an electron microprobe. An effect or orientation differences was observed on the specimen current of the electron microprobe. This effect was attributed to a channelling phenomenon. The influence of ths channelling effect on quantitative analyses by electron microprobe was considered for the precipitated a-phase and matrix β-phase, and the massive a precipitates were found to consist of many crystallites having different orientations. From the lattice constant of the g-phase determined by the Kossel patterns, the concentration of zinc at the target point was obtained in good agreement with the value obtained by quantitative analyses using an electron microprobe. Thus, in some cases, the Kossel technique can be utilized for the quantitative analysis of a small portion without any corrections which are necessary In the case of electron microprobe.

Applications of Through-Focus Dark Field Image Shifts to Phase Identification

1975 ◽  
Vol 33 ◽  
pp. 178-179
Author(s):  
Prakash Rao
Keyword(s):  
Dark Field Image ◽  
Thin Foil ◽  
Dark Field ◽  
The Other ◽  
Stereo Image ◽  
Phase Identification ◽  
The Past ◽  
Field Electron Microscopy ◽  
Dark Field Electron ◽  
Recent Extension

Image shifts in out-of-focus dark field images have been used in the past to determine, for example, epitaxial relationships in thin films. A recent extension of the use of dark field image shifts has been to out-of-focus images in conjunction with stereoviewing to produce an artificial stereo image effect. The technique, called through-focus dark field electron microscopy or 2-1/2D microscopy, basically involves obtaining two beam-tilted dark field images such that one is slightly over-focus and the other slightly under-focus, followed by examination of the two images through a conventional stereoviewer. The elevation differences so produced are usually unrelated to object positions in the thin foil and no specimen tilting is required.In order to produce this artificial stereo effect for the purpose of phase separation and identification, it is first necessary to select a region of the diffraction pattern containing more than just one discrete spot, with the objective aperture.

Reparação óssea no implante dental

2020 ◽  
Vol 12 (45) ◽  
pp. 63-66
Author(s):  
Halim Nagem Filho ◽  
Reinaldo Francisco Maia ◽  
Reinaldo Missaka ◽  
Nasser Hussein Fares
Keyword(s):  
Gene Expression ◽  
Titanium Surface ◽  
Close Contact ◽  
The Other ◽  
Main Function ◽  
Indirect Interaction ◽  
M2 Macrophages ◽  
Activated Macrophages ◽  
M1 Macrophages ◽  
High Production

The osseointegration is the stable and functional union between the bone and a titanium surface. A new bone can be found on the surface of the implant about 1 week after its installation; the bone remodeling begins between 6 and 12 weeks and continues throughout life. After the implant insertion, depending on the energy of the surface, the plasma fluid immediately adheres, in close contact with the surface, promoting the adsorption of proteins and inducing the indirect interaction of the cells with the material. Macrophages are cells found in the tissues and originated from bone marrow monocytes. The M1 macrophages orchestrate the phagocytic phase in the inflammatory region and also produce inflammatory cytokines involved with the chronic inflammation and the cleaning of the wound and damaged tissues from bacteria. On the other hand, alternative-activated macrophages (M2) are activated by IL-10, the immune complex. Its main function consists on regulating negatively the inflammation through the secretion of the immunosuppressant IL-10. The M2 macrophages present involvement with the immunosuppression, besides having a low capacity for presenting antigens and high production of cytokines; these can be further divided into M2a, M2b, and M2c, based on the gene expression profile.

STUDI OF FRUIT LEATHER PROCESSING OF MANGGO

2013 ◽  
Vol 3 (2) ◽  
pp. 124-132
Author(s):  
Yessy Rosalina ◽  
Laili Susanti ◽  
Tatik Sulasmi
Keyword(s):  
Thin Sheet ◽  
Physical Appearance ◽  
The Other ◽  
Drying Temperature ◽  
Fruit Flesh ◽  
Leather Processing ◽  
High Yielding Varieties ◽  
Processing Techniques

Mango varieties Bengkulu is one of high yielding varieties from Bengkulu Province. The plants grow well and produce fruits almost year-around in all regions in the province of Bengkulu. Mango varieties Bengkulu have very large fruit, thick fruit flesh and slightly sour flavors. It makes Mango varieties Bengkulu is very suitable to be consumed in the form of a processed. Fruit leather is one form of processed fruit. Fruit leather is a thin sheet of fruit in dried form. The results showed that the best processing techniques of fruit leather for mango varieties Bengkulu is the process with addition of sugar by 20% and drying temperature at 60 ?C. The treatment produce fruit leather with the best physical appearance and flavor compared with the other treatments.

Brittle-ductile transition of titanium aluminides, alloyed by β-phase stabilization elements

2020 ◽  
Vol 2020 (01) ◽  
pp. 86-97
Author(s):  
M. V. Remez ◽  
◽  
Yu. M. Podrezov ◽  
V. I. Danylenko ◽  
M. I. Danylenko ◽  
...  
Keyword(s):  
Plastic Zone ◽  
Grain Boundaries ◽  
Titanium Aluminides ◽  
Elevated Temperatures ◽  
Rate Sensitivity ◽  
Relaxation Processes ◽  
Main Role ◽  
Β Phase ◽  
Brittle Ductile Transition ◽  
Phase Stabilization

The temperature, structural, and rate sensitivity of the plasticity characteristics in γ-tita¬nium aluminides with different Al contents, doped with β-phase stabilization elements, are studied. Particular attention is paid to dislocation mechanisms that control the brittle-plastic transition. The main role of grain boundaries in the formation of plasticity characteristics is demonstrated. At low temperatures, the grain boundaries stop propagation of brittle transgranular cracks and confine the development of the plastic zone beyond the boundaries of an individual grain, creating the prerequisites for fracture in the microdeformation level. At elevated temperatures, the boundaries contribute to the formation of dislocations pile-up in the plastic zone with a stress concentration required to set off the Frank-Reed sources and the displacement of the plastic zone beyond the boundaries of an individual grain, changing its configuration and stress distribution and inhibiting the propagation of cracks. Acceleration of rela¬xation processes in the vicinity of the crack’s tip creates the prerequisites for the development of macrodeformation. Local relaxation processes at the crack’s tip contribute to high speed sensitivity of the plasticity characteristics. This effect has important practical consequences, since there is a temperature region near the upper working temperature of γ-TiAl alloys, where the stress value remains high (yield strength σ02 ~700 MPa and ultimate stress σul ~ 1200 MPa at bending tests) regardless of the strain rate, while deformation sharply increases at low speeds. As a result, it is possible to achieve a combination of high strength and ductility during creep tests. In samples tested by tension with low speed (10-5 s-1) the neck formation take a place. Deformation occurs by the dislocation-twinning mechanisms. At small deformations (7%) a twinning mechanism is preferable. Concentration of dislocations sharply increases at large deformations (32%) with formation of dislocation clusters. Stress relaxation on the boundary between γ-phase twins and α2-lamella, occurs by macroscopic shift on α2-lamella. Keywords: γ-titanium-aluminides, structure, strength, plasticity, brittle-ductile transition, temperature and rate sensitivity.

Copper-zinc alloys (brass)

2008 ◽  
Author(s):  
Peter Drodten ◽  
Roman Bender
Keyword(s):  
Zinc Alloys ◽  
Copper Zinc

Newly Developed Heat Resistant Magnesium Alloy by Thixomolding®

2005 ◽  
Vol 488-489 ◽  
pp. 287-290 ◽  
Author(s):  
Tadayoshi Tsukeda ◽  
Ken Saito ◽  
Mayumi Suzuki ◽  
Junichi Koike ◽  
Kouichi Maruyama
Keyword(s):  
Aluminum Alloy ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Die Casting ◽  
The Other ◽  
Heat Resistant ◽  
Higher Temperature ◽  
Better Than

We compared the newly developed heat resistant magnesium alloy with conventional ones by Thixomolding® and aluminum alloy by die casting. Tensile properties at elevated temperatures of AXEJ6310 were equal to those of ADC12. In particular, elongation tendency of AXEJ6310 at higher temperature was better than those of the other alloys. Creep resistance of AXEJ6310 was larger than that of AE42 by almost 3 orders and smaller than that of ADC12 by almost 2 orders of magnitude. Fatigue limits at room temperature and 423K of AXEJ6310 was superior among conventional magnesium alloys.

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