Observations of the Cell Structure of Heavily Rolled Phosphor Bronze

1973 ◽  
Vol 31 ◽  
pp. 162-163
Author(s):  
R. N. Caron ◽  
S. Shapiro
Keyword(s):  
Cell Structure ◽  
Rolling Plane ◽  
Average Thickness ◽  
Rolled Sample ◽  
Final Thickness ◽  
Standard Methods ◽  
Thin Foils ◽  
Transmission Electron ◽  
Cold Rolled ◽  
Cold Worked

Transmission electron microscopy has often been used to observe the nature of the heavily cold worked condition in metals in order to evaluate the effect of this microstructure on subsequent processes and properties. However, interpretation of a heavily cold rolled microstructure when viewed normal to the rolling plane is made difficult by the fact that the average thickness of the elongated cells resulting from such deformation is often smaller than the thickness of the foil. The final thickness of a heavily rolled structure is often too thin for convenience in making thin foils trans- verse to the rolline plane. The technique of plating copper to thicken the thin cold rolled sample sufficiently for om pat ibility with standard methods for preparing transmission foils has been successfully used.

Investigations of HAVAR® Alloy Using Positrons

2012 ◽  
Vol 331 ◽  
pp. 95-112 ◽  
Author(s):  
S. May Tal Beck ◽  
Wolfgang Anwand ◽  
Andreas Wagner ◽  
Gerhard Brauer ◽  
A. Beck ◽  
...  
Keyword(s):  
Lattice Structure ◽  
Positron Beam ◽  
Positron Annihilation Spectroscopy ◽  
Total Charge ◽  
Slow Positron ◽  
Positron Spectroscopy ◽  
Thin Foils ◽  
Transmission Electron ◽  
Cold Rolled ◽  
Proton Dose

A study of irradiation-induced damage in HAVAR® foils was initiated in order to extract the highest proton dose the foils can sustain. The lattice structure of HAVAR® foils in different metallurgic conditions is presented, as well as visible internal structure, measured by Transmission Electron Microscopy (TEM). Positron Annihilation Spectroscopy (PAS) techniques were used to investigate these foils, and another foil that had been irradiated to the maximal proton dose limit, set by the manufacturer to a total charge of 1 mAh (= 3.6 C). PAS techniques included Doppler broadening (DB) measurement in the SPONSOR beam and lifetime (LT) measurements, both carried at Helmholtz-Zentrum Dresden-Rossendorf (HZDR). Both positron spectroscopy methods show clear differences between the investigated foils, with distinguished characteristics for annealed, cold-rolled and irradiated foils. The advantages of using a slow positron beam to study thin foils and defect profiles, over a table-top LT spectrometer, are discussed and demonstrated by the HAVAR® measurements.

On the disappearance of fine, disc-like features from thin foils of steel

1991 ◽  
Vol 49 ◽  
pp. 608-609
Author(s):  
S. W. Thompson
Keyword(s):  
Room Temperature ◽  
Sheet Steel ◽  
Rolled Sheet ◽  
Steel Company ◽  
Thin Foils ◽  
Transmission Electron ◽  
Fine Carbide ◽  
Iced Water ◽  
Cold Rolled ◽  
Carbide Particles

Fine carbide particles form in quenched-and-aged specimens of iron containing a small amount of carbon. Similar precipitation occurs in ferrite grains within dual-phase steels. The particles have been described as discs or loops, typically about 20 run in diameter and 2 nm thick, which lie on ﹛100﹜ planes within ferrite grains. The precipitates are believed to form in association with vacancies and produce increases in hardness and yield strength. Two studies showed that these features disappeared after heating specimens in the transmission electron microscope (TEM), and this note reports further on this phenomenon.Continuously annealed and cold-rolled sheet steel (provided by Inland Steel Company) contained (in wt pet) 0.087 C, 0.97 Mn, 0.27 Si, 0.034 Al, 0.008 S, and 0.005 N. Specimens were intercritically annealed at 770°C for five minutes and quenched in iced water. Tensile testing was conducted within one day of heat treatment, and then specimens were stored at room temperature for about six months. Thin foils were produced by conventional thinning methods and jet polished at 75 V and 80 mA in an electrolyte containing 95% acetic acid and 5% perchloric acid. Specimens were examined in a Philips EM400 operated at 120 kV.

Microstructures and Properties of Cu-Cr-Y Alloy after Cold Worked and Aging

2011 ◽  
Vol 194-196 ◽  
pp. 1301-1304
Author(s):  
Shou Hui Guo ◽  
Meng Zhang ◽  
Guo Yin Peng ◽  
Jian Cheng Tang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Solid Solution ◽  
Supersaturated Solid Solution ◽  
Solution Treated ◽  
Transmission Electron ◽  
Peak Aged ◽  
Cold Rolled ◽  
Cold Worked ◽  
Hardening Condition

The influence of cold-worked and aging processes on the microstructures, mechanical properties and conductivity of Cu-Cr-Y alloy has been experimentally investigated. Samples were cut from ingot of Cu-0.8 wt.%Cr-0.05 wt.%Y alloy. They were solution-treated, cold rolled and aging treated. The results show that the Cu-Cr-Y alloy, with 70% deformation and aging at 480°C for 24min, can reach an excellent combination of microhardness and conductivity. The microhardness and conductivity is about 143HV and 84%IACS, respectively. The microstructures by transmission electron microscopy (TEM) show that the fine and dispersed distributed Cr precipitate, which form due to decomposition of the supersaturated solid solution during aging, is responsible for the peak maximum microhardness as it is predominantly present in the peak aged hardening condition.

Investigation of structurally less-ordered areas in the Nb filaments of a heavily cold-rolled Cu-20 wt. % Nb in situ composite

1995 ◽  
Vol 10 (12) ◽  
pp. 3050-3061 ◽  
Author(s):  
D. Raabe ◽  
U. Hangen
Keyword(s):  
Large Strain ◽  
High Strength ◽  
Structural Regularity ◽  
Transmission Electron ◽  
Hardening Models ◽  
Dislocation Cells ◽  
Cold Rolled ◽  
Cold Worked ◽  
The Impact

A fiber-reinforced in situ metal matrix composite (MMC) consisting of copper (Cu) and 20 mass% niobium (Nb) was produced by large strain cold rolling. The rolled MMC revealed a very high strength combined with good electrical conductivity. The microstructure of single Nb filaments was investigated employing transmission electron microscopy (TFM). In heavily rolled specimens (∊max = 99.4%) randomly arranged dislocations as well as dislocation cells were observed. Furthermore, structurally less-ordered areas were discovered, the size of which frequently extended over the entire filament width. The shrinkage of these zones during heating was directly observed in the TEM. The impact of such structurally less-ordered areas on the strength was assessed. The discovery of the degradation of structural regularity in the Nb filaments of heavily cold-worked Cu-20 wt. % Nb shows that the underlying microstructural mechanisms responsible for the high strengths observed are far from being understood and that the strain-hardening models for Cu-based in situ composites currently discussed do not yet account for all relevant microstructural features.

Development of substructure in 1100 aluminum during cold rolling

1978 ◽  
Vol 36 (1) ◽  
pp. 596-597
Author(s):  
D.L. Rohr ◽  
S.S. Hecker
Keyword(s):  
Room Temperature ◽  
Mechanical Response ◽  
Large Strains ◽  
Plastic Response ◽  
Final Thickness ◽  
Commercially Pure ◽  
Thin Foils ◽  
Transmission Electron ◽  
Aluminum Plates ◽  
Comprehensive Study

The plastic response of metals at very large plastic strains is of considerable interest for practical and academic reasons. The question of the existence of a saturation stress remains largely unanswered because most experiments are not carried out to sufficiently large strains. In this paper we report our preliminary findings on the development of substructure in 1100 aluminum during rolling to reductions of 99.8%. This is part of a comprehensive study of microstructure and mechanical response of metals to large uniaxial and biaxial deformations.Commercially pure (1100) aluminum plates, annealed at 500°C, were rolled at room temperature from various starting thicknesses to a final thickness of 0.127 mm in a 2-high laboratory rolling mill. Sheets with final reductions ranging from 9.1 to 99.8% were examined by transmission electron microscopy. Thin foils were prepared directly from the 0.127-mm thick sheets by electropolishing with a 50cc-50cc-2cc HNO3-CH3OH-HCl solution in a jet polisher.

Effect of Severe Cold-Rolling and Subsequent Annealing on Microstructure and Properties of in-Situ Composite Steel

2010 ◽  
Vol 667-669 ◽  
pp. 157-160
Author(s):  
Jun Zhao ◽  
Han Zhang ◽  
Yong Ming Yang ◽  
Jiu Chuan Chen ◽  
Quan Xing Wen ◽  
...  
Keyword(s):  
Cold Rolling ◽  
Lath Martensite ◽  
Rolling Plane ◽  
Subsequent Annealing ◽  
Rolled Sample ◽  
In Situ Composite ◽  
Cold Rolling And Annealing ◽  
Cold Rolled ◽  
Equiaxed Grains

In this paper, the process of severe cold-rolling and annealing for Q235 steel with lath martensite has demonstrated a new promising technique for producing in-situ composite multi-nanolayer steel. Cold rolling and subsequent annealing have great impact on microstructure evolution as well as mechanical properties. In the as-rolled state, the strength (b 2112 MPa) is approximately four times increased than as-received material, which is attributed to work hardening and grain refining during cold rolling. As cold-rolled sample subjected to further annealing below 500 °C, deformed microstructure underwent further recovery and recrystallization and finally became refined equiaxed grains; ultrafine ferrite grains, nano-carbides precipitated uniformly were seen in the specimen annealed at 500 °C, and the phenomenon of fracture delamination was observed from the specimens, the delamination plane was parallel to the rolling plane, in-situ composite weak interfaces effect has great impact on the fracture surface. Annealing at and above 600 °C resulted in coarse ferrite grains with spheroidized coarse carbides, causing grain growth.

Phenomena Associated with Oxygen in Titanium

1967 ◽  
Vol 25 ◽  
pp. 310-311
Author(s):  
E. U. Lee ◽  
P. A. Garner ◽  
J. S. Owens
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Microstructural Changes ◽  
Electrolytic Polishing ◽  
Interstitial Impurities ◽  
Thin Foils ◽  
Transmission Electron ◽  
Iodide Titanium ◽  
Alpha Titanium

Evidence for ordering (1-6) of interstitial impurities (O and C) has been obtained in b.c.c. metals, such as niobium and tantalum. In this paper we report the atomic and microstructural changes in an oxygenated c.p.h. metal (alpha titanium) as observed by transmission electron microscopy and diffraction.Oxygen was introduced into zone-refined iodide titanium sheets of 0.005 in. thickness in an atmosphere of oxygen and argon at 650°C, homogenized at 800°C and furnace-cooled in argon. Subsequently, thin foils were prepared by electrolytic polishing and examined in a JEM-7 electron microscope, operated at 100 KV.

Simulation of three Dimensional Defect Images in Transmission Electron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 470-471
Author(s):  
W. D. Cooper ◽  
C. S. Hartley ◽  
J. J. Hren
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Three Dimensional ◽  
Crystalline Lattice ◽  
Continuum Models ◽  
Thin Foils ◽  
Transmission Electron ◽  
Microscope Images ◽  
General Computer Program ◽  
General Computer

Interpretation of electron microscope images of crystalline lattice defects can be greatly aided by computer simulation of theoretical contrast from continuum models of such defects in thin foils. Several computer programs exist at the present time, but none are sufficiently general to permit their use as an aid in the identification of the range of defect types encountered in electron microscopy. This paper presents progress in the development of a more general computer program for this purpose which eliminates a number of restrictions contained in other programs. In particular, the program permits a variety of foil geometries and defect types to be simulated.The conventional approximation of non-interacting columns is employed for evaluation of the two-beam dynamical scattering equations by a piecewise solution of the Howie-Whelan equations.

TEM study on fine carbide precipitates and dislocation cell structure

1990 ◽  
Vol 48 (4) ◽  
pp. 904-905
Author(s):  
Mengzhe Chen ◽  
Siqin Wang ◽  
Jun Ke
Keyword(s):  
Carbide Particle ◽  
Cell Structure ◽  
Ferrite Matrix ◽  
Dislocation Cell ◽  
Isothermal Treatment ◽  
Particle Sizes ◽  
Dislocation Cell Structure ◽  
Thin Foils ◽  
Hsla Steels ◽  
Fine Carbide

A series of investigations have been conducted into the nature and origin of the dislocation cell structure. R.J.Klassen calculated that the dislocation cell limiting size in pure ferrite matrix is about 0.4 μm. M.N.Bassion estimated the size of dislocation cell in deformed ferrite of HSLA steels to be of the same order.In this paper, TEM observation has been concentrated on the interaction of fine carbide precipitates with dislocation cell structure in deformed Fe-C-V (0.05%C, 0.13% and 0.57%V) and Fe-C-Nb (0.07 %C and 0.04%Nb) alloys and compared with that in Fe-C (0.05%). Specimens were austenitized at 1500 “C/20 min and followed by isothermal treatment at 750 °C and 800 “C for 20, 40 and 120 minutes . The carbide particle sizes in these steels are from 9 to 86nm measured from carbon extraction replicas. Specimens for TEM were cut from differently deformed areas of tensile specimens deformed at room temperture. The thin foils were jet electropolished at -20 C in a solution of 10% perchloric acid and 90% ethanol. The TEM observation was carried out in JEM 100CX , EM420 at 100kv and JEM 2000FX at 200kv.

An EBSD Study on Orientation Effects during Recrystallization of Coarse-Grained Niobium

2004 ◽  
Vol 467-470 ◽  
pp. 519-524 ◽  
Author(s):  
Hugo Ricardo Zschommler Sandim ◽  
Dierk Raabe
Keyword(s):  
Longitudinal Section ◽  
Primary Recrystallization ◽  
Coarse Grained ◽  
Subgrain Structure ◽  
Electron Backscattered Diffraction ◽  
Subgrain Growth ◽  
Metallographic Inspection ◽  
Cold Rolled ◽  
Cold Worked ◽  
Viable Mechanism

The recrystallization behavior of coarse-grained niobium depends on the nature of its deformation microstructure. In this regard, a longitudinal section of a high-purity coarse-grained niobium ingot was cold rolled to a thickness reduction of 96% followed by annealing in vacuum at 800°C for 1 h. Metallographic inspection in cold-rolled and annealed specimens was carried out in a field emission gun scanning electron microscope (FEG-SEM). Microtexture was determined by electron-backscattered diffraction (EBSD) coupled to the FEG-SEM. The use this technique has evidenced details of the boundary character and subgrain structure found in partially recrystallized regions. The early stages of primary recrystallization are associated to the presence of high-angle lamellar boundaries found in the cold-worked state. Abnormal subgrain growth has been evidenced as a viable mechanism for nucleation of recrystallization.

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