scholarly journals Effects of Various Corrosive Ions on Metakaolin Concrete

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1108
Author(s):  
Xupeng Chen ◽  
Zhuowen Sun ◽  
Jianyong Pang
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Magnesium Hydroxide ◽  
Final Stage ◽  
Interaction Mechanism ◽  
Physical And Mechanical Properties ◽  
Reciprocal Inhibition ◽  
Ion Content ◽  
Microstructural Changes ◽  
Concrete Corrosion

In order to study and verify if the three corrosive irons of SO42−, Mg2+, and Cl− could promote or inhibit each other in concrete corrosion as time goes by, we take Metakaolin (MK) as the research object to explore the interaction mechanism among ions by testing the physical and mechanical properties, the ion content, the phase composition, and the microstructural changes of the MK concrete under the action of various ion combinations. The results show that during the initial and middle stages of the corrosion (40–80 days), SO42− and Mg2+ are in reciprocal inhibition relation, Cl− could inhibit the action of SO42−, and Mg2+ could promote the diffusion of Cl−. However, at the final stage of corrosion (120 days), SO42− and Mg2+ could mutually promote each other, and both irons could promote the diffusion of Cl−. Mg2+ could mainly produce magnesium hydroxide and M-S-H inside the concrete, SO42− mainly generates the ettringite and gypsum, while Cl− mainly produces Friedel salt and NaCl crystal.

Heat treatememt effect on microstructure and mechanical properties of precipitation hardening elinvar alloy

2021 ◽  
pp. 68-73
Author(s):  
G.V. Shlyakhova ◽  
◽  
A.V. Bochkareva ◽  
M.V. Nadezhkin ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Phase Composition ◽  
Structural Analysis ◽  
Thermal Treatment ◽  
Precipitation Hardening ◽  
Physical And Mechanical Properties ◽  
Alloy Structure ◽  
Treatment Mode ◽  
Elinvar Alloy

This study presents experimental results of structural analysis, such as phase composition, grains size assessment, strength and hardness of Ni-SPAN-C alloy 902 after various heat treatment modes (hardening and aging for stress relaxation). A thermal treatment mode has been selected to obtain higher physical and mechanical properties of the elinvar alloy. It is shown that the improvement of the alloy structure in thermal treatment occurs due to the thermic stresses, as well as the formation and dissolution of intermetallides.

Production of mullite‒TiC‒с-BN‒с-ZrO2-materials by the method of plasma-spark sintering and their properties

2019 ◽  
pp. 23-29 ◽  
Author(s):  
A. V. Hmelov
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Elastic Modulus ◽  
Linear Correlation ◽  
Modulus Of Elasticity ◽  
Physical And Mechanical Properties ◽  
Linear Shrinkage ◽  
Physicomechanical Properties ◽  
Intensive Development ◽  
Crystalline Microstructure

The effect of different с-BN and с-ZrO2 ratios on the phase composition, microstructure, relative density, open porosity, linear shrinkage, physicomechanical properties, and linear correlation of the elastic modulus and toughness of samples during plasma-spark sintering at pressing load 70 MPa in the range of 1200‒1600 °C is shown. The synthesized powders of TiC, c-BN and c-ZrO2, sintered at 1400 °C by the plasma-spark method, are characterized by intense crystallization of the phases. Sintered samples with different ratios of c-BN and c-ZrO2 show the intensive development of mullite and TiC. An increase in the c-BN / c-ZrO2 ratio promotes an active increase in c-BN and a less intensive increase in с-ZrO2 in the range of 1200‒1600 °C, and it causes the formation of a less uniform and densely sintered crystalline microstructure with a large number of pores at 1500 °C. This sample has lower values of physical and mechanical properties and a lower linear correlation of the modulus of elasticity and toughness in the range of 1200‒1600 °C and lower crack resistance at 1500 °C. Ill. 9. Ref. 13. Tab. 1.

Microstructure, Phase Composition, Physical and Mechanical Properties of Titanium Alloy VT23 Hot-Extruded Tube

2021 ◽  
Vol 410 ◽  
pp. 324-329
Author(s):  
Fedor V. Vodolazskiy ◽  
Anatoliy G. Illarionov ◽  
Natalya A. Shirinkina
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Phase Composition ◽  
Phase State ◽  
Physical And Mechanical Properties ◽  
Transmission Microscopy ◽  
X Ray ◽  
Structure Phase ◽  
Close Relationship ◽  
Alloy Vt23

Macro-, microstructural, fine structure, phase composition, texture and complex of physical and mechanical properties in titanium alloy VT23 (Ti-5.5Al-4.7V-2.5Mo-1.1Cr-0.7Fe, wt. %) tube were studded by the macroanalysis, optical and transmission microscopy, X-ray phase analysis, durometry and microindentation methods. A close relationship between the structural-textural-phase state formed during the extrusion and the obtained level of strength, plastic, durometric properties and the contact modulus of elasticity in a hot-extruded tube has been established.

Characteristics of Pre-Alloyed Powders for Diamond Tools

2007 ◽  
Vol 534-536 ◽  
pp. 1093-1096
Author(s):  
Xi Yu Luo ◽  
Ming Qiang Tang ◽  
Xing Kuang ◽  
Man Huang ◽  
Hong Qiu Ma
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Physical And Mechanical Properties ◽  
Low Temperature Sintering ◽  
Bend Strength ◽  
Diamond Tools ◽  
Bending Modulus ◽  
Fine Cobalt ◽  
Water Atomization ◽  
Sintering Characteristics

In this paper, the fundamental attributes, phase composition of three pre-alloyed powders for diamond tools by water atomization were investigated. The density, hardness, bend strength and bending modulus of their sintered samples by hot pressing were examined under various temperatures. The results showed that the three pre-alloyed powders have excellent low temperature sintering characteristics. The physical and mechanical properties of the samples were found to be nearly the same as those of ultra-fine cobalt powders.

Production of an Electrolytic Alloy Nickel-Tin-Bor

2019 ◽  
Vol 945 ◽  
pp. 712-717
Author(s):  
A.V. Khramenkova ◽  
K.A. Shpanova ◽  
D.N. Ariskina
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Phase Composition ◽  
Nickel Alloy ◽  
Electrical Resistance ◽  
Physical And Mechanical Properties ◽  
Electrolyte Composition ◽  
Spreading Coefficient ◽  
Electrolytic Coating ◽  
Chloride Electrolyte

A method for the preparation and properties of an alloy based on nickel is discussed. An electrolyte for the deposition of a tin-nickel alloy has been developed. The influence of electrolysis regimes and electrolyte composition on the physical and mechanical properties (microhardness, spreading coefficient of solder, transient electrical resistance, coating ability to soldering, phase composition, porosity, adhesion, corrosion resistance) of an electrolytic coating based on nickel-tin alloy precipitated from a chloride electrolyte. The possibility of using a tin-nickel alloy as a solderable coating instead of gold and silver is shown.

Phase composition-dependent physical and mechanical properties of YbxZr1−xO2−x/2 solid solutions

2008 ◽  
Vol 69 (4) ◽  
pp. 805-814 ◽  
Author(s):  
M. Hartmanová ◽  
F. Kubel ◽  
V. Buršíková ◽  
E.E. Lomonova ◽  
J.P. Holgado ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Phase Composition ◽  
Solid Solutions ◽  
Physical And Mechanical Properties

Nanostructured strain-hardened aluminum-magnesium alloys modified by C60 fullerene obtained by powder metallurgy Part 2. The effect of magnesium concentration on physical and mechanical properties

2020 ◽  
pp. 76-84
Author(s):  
I. A. Evdokimov ◽  
R. R. Khayrullin ◽  
R. Kh. Bagramov ◽  
S. A. Perfilov ◽  
A. A. Pozdnyakov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Phase Composition ◽  
Composite Materials ◽  
Powder Metallurgy ◽  
Physical And Mechanical Properties ◽  
Grain Structure ◽  
Magnesium Concentration ◽  
Mechanically Alloyed ◽  
Aluminum Magnesium Alloys

This paper is intended to continue the studies of magnesium effects on the structural phase composition, physical and mechanical properties of the nanostructured strain-hardened aluminum-magnesium alloys modified with C60 fullerene [1]. Previously obtained mechanically alloyed composite powders [1] were consolidated by direct hot extrusion method. Consolidation parameters were chosen based on previous studies of the structure and phase composition formation during mechanical alloying and heat treatment. It was found that an increase in magnesium concentration improves mechanical properties of extruded nanosructured composite materials, and additives modified by C60 fullerene stabilize the grain structure and slow down decomposition of α solid solution of magnesium in aluminum to 300 °C. Under similar thermobaric treatment Al82Mg18 (AMg18) not modified with C60 demonstrates a reduced α solid solution lattice constant and an increased average crystallite size. These processes are accompanied by sequential formation of γ, β′, and β phases, while γ and β′ are intermediate phases. The grain structure of extruded samples is typical for materials obtained in this way – grains are closely packed, elongated and oriented along the extrusion axis. The grain structure of extruded samples inherits the morphology of mechanically alloyed powders. Thus, mechanical alloying methods followed by intense plastic deformation (extrusion) improved mechanical properties significantly. Materials with ultimate tensile strength of 880 MPa; ultimate bending strength of 1100 MPa; microhardness up to 3300 MPa; and with the same density of 2.4–2.6 g/cm3 were obtained. This result demonstrates the prospects for using powder metallurgy techniques in the production of new nanostructured composite materials modified by C60 fullerene with improved physical and mechanical properties.

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