scholarly journals Influence of chemical composition and the processing conditions on structure, thermal stability and mechanical properties of rapidly cooled Al-TM-RE-based alloys

2021 ◽  
Vol 29 (1) ◽  
pp. 29-40
Author(s):  
V. K. Nosenko ◽  
T. M. Mika ◽  
V. A. Mashira ◽  
O. Kandaurov ◽  
O. M. Semirga ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Chemical Composition ◽  
Structural Features ◽  
Amorphous Structure ◽  
Alloying Elements ◽  
Continuous Heating ◽  
Rapidly Quenched Alloys ◽  
Temperature Ranges ◽  
Bulk Nanocrystalline ◽  
Melt Cooling

The results of t studies are directed to development of new competitive amorphous and nanocrystalline alloys as well as to improvement of technology of their manufacturing. The physical and technological aspects of interrelations between the conditions for production of rapidly quenched alloys, formation of different structural and phase states, and their properties are discussed. The influence of the chemical composition of alloys and the conditions of their quenching on the glass-forming ability, phase composition, and the structure of the rapidly cooled specimens is investigated; the regularities of the effect of alloying elements concentration on the structural features of the Al75–87(Ni,Co,B/Ga)8–20Gd1Y4 alloys obtained by superfast quenching from the liquid state are established. The thermal stability of the rapidly quenched ribbons with an amorphous structure is investigated and the temperature ranges of phase transformations at continuous heating and under isothermal conditions are found. The strength characteristics of the ribbons as a function of the content and nature of alloying elements as well as the melt cooling rate are determined. The methods of obtaining both Al-based bulk nanocrystalline composites with the shapes of rods and plates with thickness of 0.5–3.5 mm and metal matrix hardening coatings are worked out.

Observations on the Structure of Ta2O5

1972 ◽  
Vol 30 ◽  
pp. 540-541
Author(s):  
P. S. Kotval ◽  
C. J. Dewit
Keyword(s):  
Electron Microscope ◽  
Structural Features ◽  
Amorphous Structure ◽  
Polished Surface ◽  
Distilled Water ◽  
Anodic Films ◽  
Amorphous Films ◽  
Beam Heating ◽  
Diffraction Patterns ◽  
Hexagonal Arrays

The structure of Ta2O5 has been described in the literature in several different crystallographic forms with varying unit cell lattice parameters. Earlier studies on films of Ta2O5 produced by anodization of tantalum have revealed structural features which are not consistent with the parameters of “bulk” Ta2O5 crystalsFilms of Ta2O5 were prepared by anodizing a well-polished surface of pure tantalum sheet. The anodic films were floated off in distilled water, collected on grids, dried and directly examined in the electron microscope. In all cases the films were found to exhibit diffraction patterns representative of an amorphous structure. Using beam heating in the electron microscope, recrystallization of the amorphous films can be accomplished as shown in Fig. 1. As suggested by earlier work, the recrystallized regions exhibit diffraction patterns which consist of hexagonal arrays of main spots together with subsidiary rows of super lattice spots which develop as recrystallization progresses (Figs. 2a and b).

Structural features and strength behavior of TRIP/TWIP steels

2020 ◽  
pp. 5-18
Author(s):  
D. V. Prosvirnin ◽  
◽  
M. S. Larionov ◽  
S. V. Pivovarchik ◽  
A. G. Kolmakov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Thermomechanical Processing ◽  
Maximum Load ◽  
Structural Features ◽  
Stacking Fault ◽  
Stacking Fault Energy ◽  
Structural And Functional Properties ◽  
Twip Steels ◽  
The Creation

A review of the literature data on the structural features of TRIP / TWIP steels, their relationship with mechanical properties and the relationship of strength parameters under static and cyclic loading was carried out. It is shown that the level of mechanical properties of such steels is determined by the chemical composition and processing technology (thermal and thermomechanical processing, hot and cold pressure treatment), aimed at achieving a favorable phase composition. At the atomic level, the most important factor is stacking fault energy, the level of which will be decisive in the formation of austenite twins and / or the formation of strain martensite. By selecting the chemical composition, it is possible to set the stacking fault energy corresponding to the necessary mechanical characteristics. In the case of cyclic loads, an important role is played by the strain rate and the maximum load during testing. So at high loading rates and a load approaching the yield strength under tension, the intensity of the twinning processes and the formation of martensite increases. It is shown that one of the relevant ways to further increase of the structural and functional properties of TRIP and TWIP steels is the creation of composite materials on their basis. At present, surface modification and coating, especially by ion-vacuum methods, can be considered the most promising direction for the creation of such composites.

Mossbauer Study of the Role of Aluminum and Chromium in Nitrogen Implanted Iron

1991 ◽  
Vol 235 ◽  
Author(s):  
M. Kopcewicz ◽  
J. Jagielski ◽  
A. Turos ◽  
D. L. Williamson
Keyword(s):  
Thermal Stability ◽  
Ion Implantation ◽  
Metallic Iron ◽  
Conversion Electron ◽  
Alloying Elements ◽  
Mössbauer Study ◽  
Conversion Electron Mössbauer Spectroscopy ◽  
Conversion Electron Mossbauer Spectroscopy ◽  
Thermal Stability Of

ABSTRACTThe role of alloying elements such as Cr and Al in the formation and stability of the nitride phases formed due to N ion implantation into metallic iron was studied by conversion electron Mössbauer spectroscopy (CEMS). The thermal stability of nitride phases upon 1 h annealing was greatly increased as a result of co-implanting either Cr or Al with N as compared to pure α-Fe implanted only with N.

scholarly journals Effect of alloying elements on thermal stability of nanocrystalline Al alloys

2021 ◽  
Vol 31 (1) ◽  
pp. 11-23
Author(s):  
Hany Rizk AMMAR ◽  
Muneer BAIG ◽  
Asiful Hossain SEIKH ◽  
Jabair Ali MOHAMMED
Keyword(s):  
Thermal Stability ◽  
Al Alloys ◽  
Alloying Elements ◽  
Thermal Stability Of ◽  
Effect Of Alloying

scholarly journals Heterogeneity of the chemical composition and thermal stability of particulate organic matter in French forest soils

Geoderma ◽  
2019 ◽  
Vol 342 ◽  
pp. 65-74 ◽  
Author(s):  
Laure Soucémarianadin ◽  
Lauric Cécillon ◽  
Claire Chenu ◽  
François Baudin ◽  
Manuel Nicolas ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Organic Matter ◽  
Chemical Composition ◽  
Particulate Organic Matter ◽  
Forest Soils ◽  
Thermal Stability Of

Microstructure Optimization in δ-TRIP Steels with Al and Nb

2018 ◽  
Vol 930 ◽  
pp. 501-506
Author(s):  
Eustáquio de Souza Baêta Júnior ◽  
Ramón Alves Botelho ◽  
Leonardo Sales Araújo ◽  
Luiz P. Brandão ◽  
Sergio Neves Monteiro
Keyword(s):  
Chemical Composition ◽  
Alloying Elements ◽  
Eutectoid Temperature ◽  
Transformation Induced Plasticity ◽  
Trip Steels ◽  
Plasticity Effect ◽  
Δ Ferrite ◽  
Areas Of Interest ◽  
Thermocalc Software ◽  
Strength And Ductility

δ-TRIP steel is a recent concept and has been developed over the last ten years aiming to combine good mechanical strength and ductility. This class of steels is multiphase and contains δ and α ferrites, as well as austenite, bainite and/or martensite. The TRIP (Transformation Induced Plasticity) effect is influenced by those phases proportion, which depends on alloying contents. This paper investigates a chemical composition that allows adequate proportion among the phases, optimizing the microstructures by means of computational methods. These microstructures are designed to contain between 10 to 50% austenite, 10 to 70% α-ferrite and 20 to 80% δ-ferrite at the eutectoid temperature. The ThermoCalc Software [1] was used to predict the fractions of the microconstituents, producing graphs describing areas of interest of microconstituents as function of alloying elements variations that leads to the desired microstructure. Results indicate that the designed volume of the phases can be found for certain proportions among the alloying elements, higher concentrations of Al and Nb combined with C allow or not the occurrence of carbides and other phases in smaller quantities.

scholarly journals Influences of Bath Chemistry and Plating Variables on Characteristics of Electroless Ni–P Films on Si Wafers from Alkaline Citrate Solutions

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Naiming Miao ◽  
Jinjin Jiang ◽  
Wangping Wu
Keyword(s):  
Thermal Stability ◽  
Chemical Composition ◽  
Deposition Rate ◽  
Electroless Nickel ◽  
Monocrystalline Silicon ◽  
P Content ◽  
Almost All ◽  
P Type ◽  
Electroless Ni ◽  
Thermal Stability Of

Electroless nickel–phosphorus (Ni–P) films were produced on the surface of p-type monocrystalline silicon in the alkaline citrate solutions. The influences of bath chemistry and plating variables on the chemical composition, deposition rate, morphology, and thermal stability of electroless Ni–P films on silicon wafers were studied. The as-deposited Ni–P films were almost all medium- and high-P deposits. The concentrations of Ni2+ and citric ions influenced the deposition rate of the films but did not affect P content in the deposits. With increasing H2PO2− content, the P content and deposition rate were steadily increased. The pH and plating temperature had a significant effect on the chemical composition and the deposition rate of the films. The thermal stability of the medium-P film was better than that of the high-P deposit. At the same time, the proposed mechanism of Ni–P films on monocrystalline silicon substrates in the alkaline bath solution was discussed and addressed.

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