Non-Equilibrium Solidification in Cu-Mg-Sn Alloys for Tribological Applications

2010 ◽  
Vol 654-656 ◽  
pp. 1393-1396 ◽  
Author(s):  
Agustín Bravo ◽  
Rafael Schouwenaars ◽  
Víctor H. Jacobo ◽  
Armando Ortiz
Keyword(s):  
Rolled Strip ◽  
Metallic Elements ◽  
Laboratory Equipment ◽  
Iron And Steel ◽  
Equilibrium Solidification ◽  
Bearing Materials ◽  
Cold Rolled ◽  
Equilibrium Phases ◽  
Equilibrium Segregation ◽  
Non Equilibrium

Mg-containing bronzes have received little attention in general technological applications due to their relatively complex processing conditions. However, Mg is one of the few metallic elements which may exhibit good tribological compatibility with iron and steel and as such is a possible candidate to replace lead in sliding bearing materials. This work describes the casting of such alloys in the form of thin ingots to produce cold rolled strip, as is done for commercial Al-Sn-based ductile triboalloys. Sound ingots could be produced with simple laboratory equipment, yielding slabs in the compositional range of Cu1Mg1Sn, Cu1Mg5Sn, Cu5Mg1Sn and Cu5Mg5Sn. Cooling curves were monitored by embedded thermocouples. Invariant points could be identified after appropriate filtering of the signal but did not correspond to the ternary equilibrium. Segregation and non-equilibrium phases were confirmed by metallography.

scholarly journals Effects of Homogenization Conditions on the Microstructure Evolution of Aluminium Alloy EN AW 8006

Metals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 419
Author(s):  
Maja Vončina ◽  
Kristijan Kresnik ◽  
Darja Volšak ◽  
Jožef Medved
Keyword(s):  
Aluminium Alloy ◽  
Thermodynamic Simulation ◽  
Casting Process ◽  
Optical Microscope ◽  
Scanning Calorimetry ◽  
Energy Dispersion Spectrometer ◽  
Thermo Calc Software ◽  
Equilibrium Solidification ◽  
Equilibrium Phases ◽  
Non Equilibrium

The industrial production of products, such as foil and aluminium alloy strips, begins with the production of semi-finished products in the form of slabs. These are produced by the continuous casting process, which is quick and does not allow the equilibrium conditions of solidification. Non-homogeneity—such as micro and macro segregation, non-equilibrium phases and microstructural constituents, as well as stresses arising during non-equilibrium solidification—are eliminated by means of homogenization annealing. In this way, a number of technological difficulties in the further processing of semi-finished products can be avoided. The aim of this research was the optimization of the homogenization annealing of the EN AW 8006 alloy. With the Thermo-Calc software, a thermodynamic simulation of equilibrium and non-equilibrium solidification was performed. Differential scanning calorimetry (DSC) was performed on selected samples in as-cast state and after various regimes of homogenization annealing and was used for the simulation of homogenization annealing. Using an optical microscope (OM), a scanning electron microscope (SEM) and an energy dispersion spectrometer (EDS), the microstructure of the samples was examined. Based on the results, it was concluded that homogenization annealing has already taken place after 8 h at 580 °C to the extent, that the material is then suitable for further processing.

Application of analytical electron microscopy to studies of equilibrium and non-equilibrium segregation in materials

1992 ◽  
Vol 50 (2) ◽  
pp. 1214-1215
Author(s):  
Edward A Kenik
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Extended Defects ◽  
Probe Diameter ◽  
Specimen Holder ◽  
Analytical Electron ◽  
Scanning Transmission ◽  
Solute Atoms ◽  
Equilibrium Segregation ◽  
Non Equilibrium

Segregation of solute atoms to grain boundaries, dislocations, and other extended defects can occur under thermal equilibrium or non-equilibrium conditions, such as quenching, irradiation, or precipitation. Generally, equilibrium segregation is narrow (near monolayer coverage at planar defects), whereas non-equilibrium segregation exhibits profiles of larger spatial extent, associated with diffusion of point defects or solute atoms. Analytical electron microscopy provides tools both to measure the segregation and to characterize the defect at which the segregation occurs. This is especially true of instruments that can achieve fine (<2 nm width), high current probes and as such, provide high spatial resolution analysis and characterization capability. Analysis was performed in a Philips EM400T/FEG operated in the scanning transmission mode with a probe diameter of <2 nm (FWTM). The instrument is equipped with EDAX 9100/70 energy dispersive X-ray spectrometry (EDXS) and Gatan 666 parallel detection electron energy loss spectrometry (PEELS) systems. A double-tilt, liquid-nitrogen-cooled specimen holder was employed for microanalysis in order to minimize contamination under the focussed spot.

Non-equilibrium segregation of boron at austenite grain boundaries

1991 ◽  
Vol 10 (20) ◽  
pp. 1232-1234 ◽  
Author(s):  
Shenhua Song ◽  
Zhexi Yuan ◽  
Tingdong Xu
Keyword(s):  
Grain Boundaries ◽  
Austenite Grain ◽  
Equilibrium Segregation ◽  
Non Equilibrium

The diffusion of non-metallic elements in iron and steel

1935 ◽  
Vol 31 ◽  
pp. 707 ◽  
Author(s):  
Arthur Bramley ◽  
Frederick Wardle Haywood ◽  
Arthur Thomas Cooper ◽  
John Thomas Watts
Keyword(s):  
Metallic Elements ◽  
Iron And Steel

Microstructure evolution in cold rolled strips during continuous annealing - modelling and simulation

2004 ◽  
Vol 120 ◽  
pp. 607-614
Author(s):  
V. Hein ◽  
H. Freydank ◽  
U. Michel ◽  
H. Zieger ◽  
G. Zouhar ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Microalloyed Steel ◽  
High Strength ◽  
Experimental Simulation ◽  
Rolled Strip ◽  
Continuous Annealing ◽  
Limited Temperature ◽  
Cold Rolled ◽  
Temperature Time ◽  
Continuous Annealing Furnace

The empirical optimization of technologies for continuous annealing of cold rolled strips is very time, material and cost intensive. The properties of cold rolled strips demanded by the customer are adjustable only in relatively closely limited temperature - time regimes. Therefore, it is a complex task to increase the performance of continuous annealing furnaces without disadvantages for the product quality. This problem can be solved by nume-rical modelling the microstructure evolution in the cold rolled strip during continuous annealing combined with experimental simulation of the annealing process. At the Institut für Werkstoffwissenschaft, Technische Universität Dresden, in co-operation with EKO Stahl GmbH, Eisenhüttenstadt, a computer program signed as TFB was deve-loped. It is suited for modelling and simulating the recrystallization kinetics in cold rolled strips during continuous annealing. Furthermore, this program can be used for optimizing the annealing technology. For example, for IF steel the pre-sent paper demonstrates to what extent the performance of a continuous annealing furnace can be increased. Further results concern the improvement of the microstructure of the high strength microalloyed steel ZStE 380 Z by optimizing the annealing technology by means of experimental simulation.

An analytical model for non-equilibrium segregation during crystallization

2004 ◽  
Vol 271 (3-4) ◽  
pp. 481-494 ◽  
Author(s):  
Kenneth A. Jackson ◽  
Kirk M. Beatty ◽  
Katherine A. Gudgel
Keyword(s):  
Analytical Model ◽  
Equilibrium Segregation ◽  
Non Equilibrium
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