scholarly journals Influence of Morphology of Intermetallic Particles on the Microstructure and Properties Evolution in Severely Deformed Al-Fe Alloys

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 815
Author(s):  
Andrey Medvedev ◽  
Maxim Murashkin ◽  
Nariman Enikeev ◽  
Evgeniy Medvedev ◽  
Xavier Sauvage
Keyword(s):  
Solid Solution ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Intermetallic Particle ◽  
Intermetallic Phase ◽  
Particle Morphology ◽  
Initial State ◽  
Intermetallic Particles ◽  
The Difference ◽  
Average Size

This study focuses on the difference in microstructural features and physical properties of Al-2Fe and Al-4Fe alloys subjected to large plastic straining. The difference in the intermetallic particle morphology in the initial state is shown to be a key parameter influencing the particle and grain fragmentation process and, as a result, the properties of these two alloys. We demonstrate that the shape and average size of Al-Fe intermetallic particles provide stronger effect on the microstructure evolution during high pressure torsion (HPT) than their volume fraction. The formation of Fe supersaturated solid solution in Al in these two alloys during deformation is discussed in connection to the morphology of the intermetallic phase. The major microstructural attributes, responsible for the solid solution formation, are highlighted.

scholarly journals Dissolution of Ag Precipitates in the Cu–8wt.%Ag Alloy Deformed by High Pressure Torsion

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 447 ◽  
Author(s):  
Anna Korneva ◽  
Boris Straumal ◽  
Askar Kilmametov ◽  
Robert Chulist ◽  
Grzegorz Cios ◽  
...  
Keyword(s):  
High Pressure ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Copper Matrix ◽  
Solubility Limit ◽  
Mixing Enthalpy ◽  
Diffusion Activation Energy ◽  
Second Phase ◽  
Silver Particles ◽  
Initial State

The aim of this work was to study the influence of severe plastic deformation (SPD) on the dissolution of silver particles in Cu–8wt.%Ag alloys. In order to obtain different morphologies of silver particles, samples were annealed at 400, 500 and 600 °C. Subsequently, the material was subjected to high pressure torsion (HPT) at room temperature. By means of scanning and transmission electron microscopy, as well as X-ray diffraction techniques, it was found that during SPD, the dissolution of second phase was strongly affected by the morphology and volume fraction of the precipitates in the initial state. Small, heterogeneous precipitates of irregular shape dissolved more easily than those of large size, round-shaped and uniform composition. It was also found that HPT led to the increase of solubility limit of silver in the copper matrix as the result of dissolution of the second phase. This unusual phase transition is discussed with respect to diffusion activation energy and mixing enthalpy of the alloying elements.

Properties of welded joints of the Al – Zn – Mg – Ca alloy doped by microadditivies of zirconium and scandium

2021 ◽  
pp. 84-92
Author(s):  
P. K. Shurkin ◽  
Zh. A. Karpova ◽  
A. F. Musin ◽  
R. A. Latypov
Keyword(s):  
Solid Solution ◽  
Base Metal ◽  
Welded Joints ◽  
Volume Fraction ◽  
Aluminum Matrix ◽  
Spherical Particles ◽  
Alloy Sample ◽  
Initial State ◽  
Microstructural Investigation ◽  
Aluminum Solid Solution

This work is devoted to the study of the structure and properties of welded joints of hot-rolled sheets from the aluminum alloy Al – 4%Zn – 2.5%Mg – 2.5%Ca – 0.2%Zr – 0.1%Sc. The joints were obtained by manual argon-arc method (TIG-welding) using a wire of own production from the base metal composition (sample AlCa) and standard welding wire Of SvAMg5 alloy (sample AlMg). It is shown that in the cast state the alloy structure consists of an aluminum solid solution (Al) (which contains 2.9% Zn, 2.5% Mg, 0.28% Zr and 0.12% Sc) and eutectic crystals of the phase (Al, Zn)4Ca with a volume fraction of ~7.6%. Microstructural investigation of wrought products showed that the formation of a structure consisting of an aluminum matrix and uniformly distributed spherical particles with a diameter of less than 2 microns occurs as a result of hot rolling with a compression ratio of 95%. The quality of welded joints produced using different additives meets the requirements for the absence of internal defects. The structure in the middle of the joints corresponds to the cast structure of the alloy and has hardness (~80 HV) inferior to the hardness (~105 HV) of the main deformed alloy. Heat-affected zone retains a relatively high hardness (at 95 HV), which is associated with a stabilizing effect of dispersed particles of the eutectic phase (Al, Zn)4Ca, and also presence of nanoparticles of the phase Al3(Zr,Sc) in the original sheet. Additional annealing of welds at 350 oC resulted in degradation of the hardness of the AlMg sample to less than 70 HV and relative cross-sectional hardness equalization in the AlCa sample to more than 90 HV. This effect can be explained by the dispersion hardening in case of the AlCa sample due to the separation of coherent nanoparticles of the Al3(Zr, Sc) phase with the L12 structure during the decay of a supersaturated aluminum solid solution. The results of mechanical tests confirmed the advantages of the strength properties of the AlCa sample over the values of the AlMg sample. All samples in the initial state and annealed sample AlMg have strength coefficients relative to the base metal from 72.4 to 75.3. The greatest mechanical properties can be achieved in the welded joint AlCa in the annealed state: UTS = 274±2 MPa, YS = 181±20 MPa, El = 2.9±0.8 %, which corresponds to a coefficient of more than 80%. This paper was prepared in the framework of the Assignment No. 11.2072.2017/4.6 for implementing a project on the following subject: Developing a process for obtaining deformed semi-finished products made of aluminium-matrix eutectic composites hardened with L12 phase nanoparticles with no quenching applied.

Impact of Non-Isothermal Warm Rolling on Microstructure, Texture and Mechanical Properties

2017 ◽  
Author(s):  
Chun Xu ◽  
Xing-zhou An ◽  
Xiao-hua Rao ◽  
Ya-nan Li
Keyword(s):  
Mechanical Properties ◽  
Warm Rolling ◽  
Initial State ◽  
Surface Temperatures ◽  
Dominant Deformation Mechanism ◽  
Complete Recrystallization ◽  
The Difference ◽  
Average Size ◽  
Cp Ti ◽  
Hot Rolled

To study the influence of non-isothermal deformation on microstructure, texture and mechanical properties, the CP Ti sheets were rolled to approximately 10% reduction per pass under a pair of rolls with different surface temperatures (i.e. non-isothermal rolled). The progress of recrystallization was enhanced with the increase of the difference in surface temperature between upper and lower rolls. When CP Ti sheets were non-isothermally rolled under the upper and lower rolls with surface temperatures of 210 and 120 °C, respectively, complete recrystallization occurred. Under such circumstances, it was found that the microstructure consists of equiaxed grains with the average size of 13μm and with mainly high-angle boundaries. Pyramidal <c+a> slip was the dominant deformation mechanism, and the elongation at room temperature was three times of that in the initial state. However, CP Ti sheets were rolled under a pair of roll with the same surface temperatures of 120 or 210 °C (i.e. isothermal rolled), recrystallization did not occur, and the microstructure, texture and mechanical properties of CP Ti isothermal rolling sheets were similar to those of conventional hot rolled CP Ti sheets.

X-Ray Analysis of α and ω – Phases of Ti, Subjected to High-Pressure Torsion

2010 ◽  
Vol 667-669 ◽  
pp. 187-192 ◽  
Author(s):  
Vil D. Sitdikov ◽  
Igor V. Alexandrov ◽  
Jan T. Bonarski
Keyword(s):  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
Crystallographic Texture ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Initial State ◽  
X Ray ◽  
Ray Patterns

This paper presents the results of experimental X-ray structural analyses of both the evolution structure and the crystallographic one in the volume of Ti samples, subjected to the Severe Plastic Deformation (SPD), realized by torsion under high pressure equal to 6 GPa at temperature 298 K. The investigations have been carried out on the disk-shaped samples with the radius of 20 mm in an initial state (the as-received state) and in the states after 0.1, 0.5, 1 and 5 rotations by High-Pressure Torsion (HPT). In the result the evolution mechanisms of the general X-ray patterns, the volume fraction of phases, the character of preferred orientations, as well as the activity of various slip and twinning systems in α- and ω-phases, depending on the SPD degree have been found out. The received results allow explaining and forecasting the behavior of nanostructured Ti, considering the parameters of its microstructure and crystallographic texture.

scholarly journals Particle Distribution and Orientation in Al-Al3Zr and Al-Al3Ti FGMs Produced by the Centrifugal Method

2005 ◽  
Vol 492-493 ◽  
pp. 609-614 ◽  
Author(s):  
P.D. Sequeira ◽  
Yoshimi Watanabe ◽  
L.A. Rocha
Keyword(s):  
Centrifugal Force ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Intermetallic Particle ◽  
Knoop Hardness ◽  
Functionally Graded ◽  
Particle Volume ◽  
Centrifugal Method ◽  
Intermetallic Particles ◽  
Force Direction

Al-Al3Zr and Al-Al3Ti functionally graded materials (FGMs) were produced by a centrifugal method from Al-5wt% Zr and Al-5wt% Ti alloys, respectively. Applied centrifugal forces were 30, 60 and 120G (units of gravity). Microstructural characterization was performed to evaluate the intermetallic particles’ distribution and orientation. Knoop hardness tests were carried out, with the indenter’s long diameter normal to the centrifugal force direction. Both the Al3Zr and the Al3Ti intermetallic particles are platelet in morphology. These platelets tend to be oriented normal to the centrifugal force direction. Higher applied centrifugal force increases both the intermetallic platelet volume fraction as well as their orientation in the outer regions of the fabricated FGM rings. Also higher orientation and volume fraction distribution are observed in the Al- Al3Ti FGMs. Knoop hardness measurements in general follow the same trend as the intermetallic particle volume fraction for each sample.

Grain Refinement in Titanium-Erbium Alloys

1974 ◽  
Vol 32 ◽  
pp. 522-523
Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Grain Refinement ◽  
Grain Growth ◽  
Volume Fraction ◽  
Pure Titanium ◽  
Systematic Investigation ◽  
Second Phase ◽  
Titanium Matrix ◽  
Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

Fine Microstructure of a Mechanically Alloyed Oxide Dispersion Strengthened Nickel-Base Superalloy

1977 ◽  
Vol 35 ◽  
pp. 298-299
Author(s):  
Jordi Marti ◽  
Timothy E. Howson ◽  
David Kratz ◽  
John K. Tien
Keyword(s):  
Solid Solution ◽  
Volume Fraction ◽  
Stress Rupture ◽  
Oxide Dispersion Strengthened ◽  
Solid Solution Alloy ◽  
Oxide Dispersion ◽  
Creep And Stress Rupture ◽  
Mechanically Alloyed ◽  
Fine Microstructure ◽  
Nickel Base

The previous paper briefly described the fine microstructure of a mechanically alloyed oxide dispersion strengthened nickel-base solid solution. This note examines the fine microstructure of another mechanically alloyed system. This alloy differs from the one described previously in that it is more generously endowed with coherent precipitate γ forming elements A1 and Ti and it contains a higher volume fraction of the finely dispersed Y2O3 oxide. An interesting question to answer in the comparative study of the creep and stress rupture of these two ODS systems is the role of the precipitate γ' in the mechanisms of creep and stress rupture in alloys already containing oxide dispersoids.The nominal chemical composition of this alloy is Ni - 20%Cr - 2.5%Ti - 1.5% A1 - 1.3%Y203 by weight. The system receives a three stage heat treatment-- the first designed to produce a coarse grain structure similar to the solid solution alloy but with a smaller grain aspect ratio of about ten.

Study of pumping effect in flow-through electrolysers

1983 ◽  
Vol 48 (8) ◽  
pp. 2232-2248 ◽  
Author(s):  
Ivo Roušar ◽  
Michal Provazník ◽  
Pavel Stuhl
Keyword(s):  
Natural Convection ◽  
Balance Equation ◽  
Volume Fraction ◽  
Industrial Applications ◽  
Pumping Effect ◽  
Flow Through ◽  
The Mean ◽  
The Difference

In electrolysers with recirculation, where a gas is evolved, the pumping of electrolyte from a lower to a higher level can be effected by natural convection due to the difference between the densities of the inlet electrolyte and the gaseous emulsion at the outlet. An accurate balance equation for calculation of the rate of flow of the pumped liquid is derived. An equation for the calculation of the mean volume fraction of bubbles in the space between the electrodes is proposed and verified experimentally on a pilot electrolyser. Two examples of industrial applications are presented.

scholarly journals The Enrichment of (Cu, Sn) Solid Solution Driven by High-Pressure Torsion

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 766
Author(s):  
Boris Straumal ◽  
Askar Kilmametov ◽  
Anna Korneva ◽  
Pawel Zięba ◽  
Yuri Zavorotnev ◽  
...  
Keyword(s):  
Solid Solution ◽  
High Pressure ◽  
Theoretical Analysis ◽  
Annealing Temperature ◽  
High Pressure Torsion

Cu–14 wt% Sn alloy was annealed at temperatures of 320 and 500 °C. The concentration of tin cinit in the copper-based matrix increased with annealing temperature. The annealed samples were subjected to high-pressure torsion (HPT) at 6 GPa, 5 turns, 1 rpa. HPT led to the refinement of Cu grains. The shape of the colonies of α + ε phases changed only slightly. The HPT-driven enrichment of the Cu-based solid solution with Sn atoms cHPT–cinit decreased with increasing cinit. The performed theoretical analysis explained this behavior of the HPT-driven enrichment.

Effect of Heat Treatment on Microstructure and Properties of Cu-3Ti-1Al Alloy

2013 ◽  
Vol 749 ◽  
pp. 282-286
Author(s):  
Xian Hui Wang ◽  
Xiao Chun Sun ◽  
Xiao Hong Yang ◽  
Shu Hua Liang
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Electrical Conductivity ◽  
Electron Microscope ◽  
Treatment Process ◽  
Intermetallic Phase ◽  
Strengthening Effect ◽  
Microstructure And Properties ◽  
Optimal Heat Treatment ◽  
Transmission Electron

The effect of heat treatment on the microstructure and properties of Cu-3Ti-1Al alloy was investigated. The microstructure was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), and the hardness and electrical conductivity were tested as well. The results showed that the hardness and electrical conductivity of Cu-3Ti-1Al alloy increased significantly after solid solution and ageing treatment. The strengthening effect of Cu-3Ti-1Al alloy was attributed to the formation of intermetallic phase such as Ti3Al and fine precipitates of coherent β-Cu4Ti. With increase of the aging time and the temperature, the precipitates became coarse and incoherent with Cu matrix, and the discontinuous precipitate β started to grow from grain boundaries toward grain interior, which decreased hardness. As the formation of Ti3Al, β-Cu3Ti and β-Cu4Ti phase can efficiently reduce Ti concentration in Cu matrix. The electrical conductivity of Cu-3Ti-1Al alloy increases. In the range of experiments, the optimal heat treatment process for Cu-3Ti-1Al alloy is solid solution at 850°C for 4h and ageing 500°C for 2h, and the hardness and electrical conductivity are 227HV and 12.3%IACS, respectively.

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