Structure Properties Of Alloys Research Articles

Influence of Aerothermoacoustic and Thermal Deformation on the Structure and Properties of Structural Alloys

Influence of Aerothermoacoustic and Thermal Deformation on the Structure and Properties of Structural Alloys

Influence of combined aerothermoacoustic and thermal deformation treatments on the structure and properties of structural alloys

The influence of thermal, thermal deformation and aerothermoacoustic (ATAT) treatments on the formation of the structure and mechanical properties of structural titanium alloys and bronzes is considered. An increase in the strength and elasticity of alloys by optimizing the modes of heat treatment, cold plastic deformation, and ATAT is shown. The influence of pre-aging treatment, aging modes and ATAT on the structure, an additional increase in the mechanical properties of alloys with preliminary hardening by quenching and cold plastic deformation is established. Keywords: titanium alloys, bronze, heat treatment, ATAT, cold plastic deformation, microstructure, mechanical properties. remshev@mail.ru, vorobiyova_galina@mail.ru, smakovskiyms@armalit1.ru, AHSW@yandex.ru

Accurate and efficient machine learning models for predicting hydrogen evolution reaction catalysts based on structural and electronic feature engineering in alloys.

Predictive materials design of high-performance alloy electrocatalysts is a grand challenge in hydrogen production via water electrolysis. The vast combinatorial space of element substitutions in alloy electrocatalysts offers a wealth of candidate materials, but presents a significant challenge in terms of experimental and computational exploration of all possible options. Recent scientific and technological developments in machine learning (ML) have offered a new opportunity to accelerate such electrocatalyst materials design. Herein, by incorporating both the electronic and structural properties of alloys, we are able to construct accurate and efficient ML models and predict high-performance alloy catalysts for the hydrogen evolution reaction (HER). We have identified the light gradient boosting (LGB) algorithm as the best-performed method, with an excellent coefficient of determination (R2) value reaching 0.921 and the corresponding root-mean-square error (RMSE) being 0.224 eV. The average marginal contributions of alloy features towards ΔGH* values are estimated to determine the importance of various features during the prediction processes. Our results indicate that both the electronic properties of constituent elements and the structural adsorption site features play the most critical roles in the ΔGH* prediction. Furthermore, 84 potential alloys with |ΔGH*| values less than 0.1 eV are successfully screened out of 2290 candidates selected from the Material Project (MP) database. It is reasonable to expect that the ML models with structural and electronic feature engineering developed in this work would provide new insights in future electrocatalyst developments for the HER and other heterogeneous reactions.

Comparative study on some structural properties of Ni- and Co base dental alloys produced by thermal alloying and powder metallurgical methods

This paper presents the results of comparative studies of nickel- and cobalt base dental alloys obtained using both the classical high-temperature alloying and the powder metallurgy (PM) methods. Structural properties of alloys were used using XRD, SEM/EDX methods of analysis. The studies examined both primary and secondary cast specimens of the two alloy types. Some advantages of the PM technology are discussed.

Fabrication and Structural Properties of Ni50 Al50 Alloy by Mechanical Alloying

In the present study, mechanical alloying process was employed for preparation of the nanocrystalline Ni50Al50 alloy through ball mill method. The structure properties of the alloy at various milling times of 0, 2, 4, 6 and 8hr were studied by X-ray diffraction and scanning electron microscopy (SEM) measurements. Several phases was formed successfully after 4hr of milling. At 6hr of milling, new intermetallic compound type (Ni3AI) was observed prospering, The particle size for various milling times decreased significantly, with increasing time of milling. The resulted morphology the milled powder shows a reduction of particle size which is in accordance with the XRD patterns. The results of EDX shows clearly atypical spectrums of both Ni and Al peaks.

Tribological properties of structural alloys for the heat exchange equipment parts subjected to fretting

Trobological characteristics of sliding friction in stainless steel and titanium alloys in dry and water lubricated conditions have been determined. The character of the coefficient of friction variation with load and the duration of tests have confi rmed the prevailing wear mechanism in these materials to be frictional fatigue fracture that in the case of titanium alloys is accompanied with adhesive interaction and plastic plowing. The frictional fatigue curves built in a result of this investigation make possible to estimate the materials tribological longevity.

Electro-Chemical Deposited Cu-Ni Binary and Cu-Ni-Mn Ternary Alloys from Sulphate Bath for Anti-Corrosive Coating Applications in Brine Environment: Effect of Corrosion Behaviour, Polarization Studies, Morphological and Structural Characterizations

Electrochemical preparation of binary alloy of Cu-Ni from acid sulphate bath containing citric acid using Potentiostatic method. The effects of alloy composition were monitored. Copper is widely used in industry, because of its good thermal conductivity and mechanical characteristics. The accumulation of Nickel & Manganese to Copper enhances itspotency, vigour, toughness, endurance, permanence&also the corrosion-resistanceas well asattrition. Corrosion controls of metal have technical environmental and economical importance. The Cu-Ni-Mn alloyswere used commercially for decorative and protective purpose and also in marine applications. The thin film coating characterized by SEM, EDAX and XRD shows morphological, compositional and structural properties of alloys respectively.

Effect of Vanadium addition on The Structural Properties of Alloy (Ni-Cu) Nano-Particles

This research aimed to prepare (Ni-Al) alloys by powder technology method because of it is technological and commercial important. Nickel and Copper powders were tacking then there powders mixed and blended together with percent (Ni-30% Cu), Vanadium powder added to matrix alloy powder with percent (0,1,2,3)% respectively then these powders mixed to obtain homogeneous powder, then the powders compacted isostatic cold pressure at (8ton). The sintering process done at (900° C) for one hour under argon gas.
 The X-ray diffractions test indicated that all alloys have Face center Cubic (F.C.C), And D alloy has best properties which include increase of phases intensity and decrease of grain size according to Debye-Scherrer equation.
 The Atomic Force Microscope (AFM) also shows better properties with increase vanadium concentration. Where increased softness of surface, homogeneity surface and decrease in grain size with increase Vanadium concentration.

INVESTIGATION OF THE INFLUENCE OF NANODISPERSED COMPOSITIONS OBTAINED BY PLASMOCHEMICAL SYNTHESIS ON THE CRYSTALLIZATION PROCESSES OF STRUCTURAL ALLOYS

The state of the problem of stabilizing the structure, improving the quality and properties of structural alloys is studied. To solve the problem, it is proposed to modify melts of low–alloyed alloys with nanodispersed compositions obtained by plasma–chemical synthesis. Process technological parameters are developed. Nanopowders of carbide and carbonitride class SiC and Ti (C, N) with a size of 50 ... 100 nm are obtained. The crystallographic parameters of the nanocompositions and the specific surface are determined, and the dependency curves are plotted. The macro– and microstructure of structural steels and alloys was studied before and after the modification. A significant (in 2 ... 3.5 times) grain refinement and stabilization of the alloy structure as a result of nanopowder modification of titanium carbonitride have been achieved. Thermodynamic calculations of the dimensions of crystalline seeds during the crystallization of steels and alloys are carried out. A complex criterial estimation of the efficiency of nanodispersed compositions in a steel melt is proposed. The features of crystallization and structure formation of modified structural steels are studied. The obtained results are of theoretical and practical importance for production of critical parts from structural steels and high–quality alloys.

Influence of Microalloying (Including Rare-Earth Metals) on the Phase Composition and Properties of Aluminum Alloys

In connection with the search for new materials and the more extensive use of metals and alloys with special physical and chemical properties, rare-earth metals (REMs) are attracting increasing interest not only as alloying additives but also as the main components of structural materials. The Al-Fe alloys are of great practical interest, and the purpose of this work was to study the influence of microalloying by REMs on the mechanical and acoustic damping properties of Al-Fe alloys. REMs were selected as alloying components because of their properties and their widespread use in improving the structure and properties of structural alloys, including mechanical and acoustic damping properties. The results of these investigations are expected to enable the use of secondary Al (i.e., waste Al manufacture with a high Fe impurity concentration) as a base material for the development of structural alloys with improved mechanical properties for use in mechanical and electrical engineering applications. The use of secondary Al will provide economic advantages and will contribute to the conservation of resources.This work is actual because Al alloyed with Fe and REMs can be used as corrosion-resistant materials and conductive materials in electronics and for automotive and aircraft engines, wires, cables, rods, tires and other products of the electrical engineering industry, thus expanding the scope of applications of these alloys [1-4].

Investigation the Structural and Magnetic Properties of FINEMET Type Alloy Produced by Mechanical Alloying

In this research, FINEMET alloy with composition of Fe73.5Si13.5B9Nb3Cu1was produced by mechanical alloying from elemental powders. The effect of milling time on the magnetic and structural properties of alloy has been investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and vibrating sample magnetometery. The results showed that milling for 53 hr leads to the formation of Fe supersaturated solid solution which includes Si, B and Nb atoms with mean crystallite size of ~30 nm. The shift of the main peak of Fe to the higher angles indicated that Si and B atoms dissolve in the Fe solid solution, at primary stage of mechanical alloying, up to the 42 hr while Nb atoms dissolve at final stages. The magnetization of milled powder for 53 hr was 173.7 emu/g, almost the same as that of the melt-spun ribbon. In addition; the coercivity reached to 15.5 Oe after 53 hr of milling. The higher value of coercivity in mechanically alloyed samples is attributed to strains induce to the structure during milling and the lack of amorphous phase and exchange interaction between nanograins.

The energetic and structural properties of bcc NiCu, FeCu alloys: A first-principles study

Using special quasirandom structures (SQS’s), we perform first-principles calculations studying the metastable bcc NiCu and FeCu alloys which occur in Fe–Cu–Ni alloy steels as precipitated second phase. The mixing enthalpies, density of states, and equilibrium lattice parameters of these alloys are reported. The results show that quasi-chemical approach and vegard rule can satisfactorily predict the energetic and structural properties of FeCu alloys but fail to accurately yield that of NiCu. The reason rests with the difference of bond energy variation with composition between NiCu and FeCu alloys induced by competition between ferromagnetic and paramagnetic state. Furthermore, the results show that the energetic and structural properties of these alloys can explain the element distribution of the Cu-rich precipitates in ferrite steels.

Effects of Simulated Pit Distribution Parameters on Tensile Properties of a Structural Steel Plate

Degradation of tensile properties resulting from geometrical discontinuities due to localized pitting is usually evaluated in terms of the reduced section thickness associated with pit geometry which lowers the load carrying capacity of the structure. However, the effects of finer parameters associated with pit distributions such as pit area percent (PAP) are not usually taken into account. In this research, the effects of spacing, depth and PAP on tensile properties of a structural steel are investigated. Simulated pit distributions were produced on the gage sections of flat tensile specimens using mechanical drilling. It is found that final elongation is more adversely affected than tensile strength with increasing PAP, pith depth and pith spacing. However, the reduction in final elongation tends to be largely recovered at higher PAP values due to increasing uniformity of strain distribution. It is noted that increasing pit spacing at a constant PAP leads to greater reductions in tensile properties, especially at higher pit depths, due to the increased stress concentration and strain localization. It is further clarifies that the introduction of first few pits and their growth to larger depths could be very detrimental to the mechanical properties of structural alloys.

Assessment of the effect of existing corrosion on the tensile behaviour of magnesium alloy AZ31 using neural networks

A concept has been devised to assess the effect of existing corrosion damage on the residual tensile properties of structural alloys and applied for the magnesium alloy AZ31. The concept based on the use of a radial basis function neural network. An extensive experimental investigation, including metallographic corrosion characterization and mechanical testing of pre-corroded AZ31 magnesium alloy specimens, was carried out to derive the necessary data for the training and the prediction module of the developed neural network model. The proposed concept was exploited to successfully predict: the gradual tensile property degradation of the alloy AZ31 to the results of gradually increasing corrosion damage with increasing corrosion exposure.

Magnetic and Structural Properties of FeCr Alloys

Synergistic synchrotron x-ray absorption experiments using imaging magnetic microspectroscopy, x-ray magnetic circular dichroism, and ab initio calculations on FeCr alloys reveal that the Cr content strongly influences the ferromagnetic microstructure and the Fe magnetic moments. The Cr local structure resolved by extended x-ray absorption fine structure (EXAFS) is also found to be affected by the alloy's composition. Both EXAFS and ab initio calculations show a change in the Cr local atomic structure above 10 at.% Cr content from the distance contraction of the first two coordination shells around the Cr absorbing atom. These results indicate the strong dependence of magnetic and structural properties of these alloys on Cr concentration.

Structural Fracture Mechanics and Control of the Properties of Structural Alloys

We outline the development of investigations founded by Karpenko and directed to the structural control of the mechanical and corrosion-mechanical properties of structural alloys. It is based on various kinds of thermal and thermomechanical treatment of such alloys as well as on the use of strengthening coatings. These works served as a basis for the study of the structural fracture mechanics of metals and alloys. We also briefly describe some results in this direction. Finally, we point out some problems of adequate evaluation of the structural strength of materials and articles, for which, by virtue of the insufficiency of the approaches of fracture mechanics as a science on the behavior of macrocracks, it is necessary to focus attention on the structurally and electrochemically dependent phenomena of crack initiation resistance.

Investigation of deformation and heat treatment effects on properties of PM 92.5W–5Ni–2.5Fe heavy alloys

This paper presents the effects of vacuum heat treatment under different cooling conditions on mechanical and structural properties of forged heavy alloys, such as 92.5W–5Ni–2.5Fe and 92.5W–5Ni–25Fe microalloyed with Co. The tungsten composition in the c phase has proved to be higher and more homogenous in the rapidly cooled alloys than in the slowly cooled ones. The effects of chemical composition inhomogeneity on mechanical and structural properties of alloys were also analysed and discussed. The results of tensile and toughness testing have shown an increase in ductility and toughness, while the strength of heat treated alloys decreased in comparison with the strength of forged alloys. The fracture analysis has shown that in the sintered and rotary forged alloys, intergranular fracture of the tungsten phase and transgranular fracture of the γ phase occurred, respectively. The fracture of these phases after heat treatment was characterised by transgranular morphology.

The deterioration of silver alloys and some aspects of their conservation

The present article aims to offer a comprehensive approach to the conservation of silver objects. It is not intended to suggest or recommend any specific recipe or treatment for a given case. Instead, the paper presents a range of possibilities to assist the conservator in defining the state of conservation and the possible need for treatment and protection of an object. Besides giving the background to the structural properties of alloys used in silver artefacts, the possible forms of silver deterioration are presented, with special emphasis on tarnishing and mineralization. Less frequent cases, such as selective, localized and stress corrosion are also discussed. A descriptive review of materials and methods used for cleaning, consolidating and protecting silver artefacts follows, accompanied by an extensive bibliography.

Mechanical, elastic, and structural properties of alloys of Ru−Ta high-temperature intermetallic compounds

Screening tests of binary high-temperature intermetallic compounds showed the Ru−Ta L10 structure to have room-temperature impact resistance and high-temperature strength. Twenty alloys based on RU11Ta9 have been studied for microhardness, elastic modulus, impact strength, and, in two cases, compressional stress-strain behavior. L10 lamallae are commonly seen, and their character on fracture surfaces correlates with relative toughness. The B2 phase is present in some alloys, also a twinned lamellar structure, and the beginnings of a martensitic transformation to the L12 form were observed in the transmission electron microscope at 93 K.

Mechanical properties of structural alloys at low temperatures

All alloys tested have satisfactory plasticity at all testing temperatures and are recommended for structures operating at temperatures from 20 to −253o, although alloy VT3-1 should be used at temperatures above −196o.