Раздел "Получение и анализ структуры материалов"

XRD patterns for Al–6 wt.% Cu alloy

Graphical abstract shows the pre-martensitic state of the FCC lattice in the CrMnN austenitic stainless steel.

The evolved microstructure was dominated by the martensitic phase, though it also contained a minor fraction (≈0.1%) of retained austenite. It was also shown the orientation relationship between the martensite and austenite deviated from the “classical” Kurdjumov-Sachs (K-S) one and could be described in terms of a mixture of the K-S and Nishiyama-Wasserman (N-W) relationships. This observation was attributed to the essential orientation spread within the prior austenite grains. Moreover, a pronounced variant selection was revealed in the martensitic phase. The reconstruction of the microstructure of the high-temperature austenite had demonstrated that the latter observation was likely due to the pronounced grain refinement and the development of a distinct B-B {110}112 simple shear texture occurring in the austenitic phase during FSP. It is believed this study broadens our current understanding of martensitic transformations in steels.

Treatment of Bi1.8Pb0.2Sr2CaCu2Oу at 700oC in an argon atmosphere leads to an increase in their critical temperatures up to 99 K.

This figure illustrates the fabrication and processing scheme of model steel walls produced using different WAAM modes (standard GMAW and coldArc). It also presents their mechanical properties, including microhardness and tensile behavior, highlighting the effects of heat treatment.

SEM fractographic image of a hydrogenated zirconium alloy, processed using VGG-16 and U-Net neural networks to determine the brittle fraction and segment brittle/ductile regions, with corresponding outputs showing the dependence of brittle fraction on hydride orientation and segmented fracture surfaces.

Pretreatment of the welded surfaces with laser radiation before diffusion welding leads to an increase in the strength of the joint due to the activation of these surfaces and, consequently, to the possibility of reducing the parameters of the diffusion welding process (temperature and welding pressure).

A thermomechanical processing mode has been developed that ensures the required structure in the Fe-Ga alloy.

The EBSD maps and ultimate strength of welded specimens for two combinations of EK61//EP741NP and VKNA-25//EP741NP.

1570C alloy after rolling at room and cryogenic temperature and subsequent electric pulse treatment

Dependence of the β-phase lattice parameter and of the Ms temperature on the d-metal concentration in the quenched zirconium-based alloys.

It was found, that a half-hour annealing in the temperature range of 250-500oC of cryorolled nickel with dislocation-cellular work-hardened structure, activated its static recovery and recrystallization.

The abrasive wear rate of PEO coating with graphene nanoparticles is 15-16% lower than that of PEO coating without additives. The micro-Raman spectra for the following hard layer indicate a significant disorder of graphene particles, a decrease in their size and the formation of SiC and carbon nanotubes inclusions.

The image shows a dark-field electron microscopy photo highlighting WTa particles, an electron diffraction pattern of these particles, and a molecular dynamics model. Calculations suggested TaW particle formation at grain boundaries and dislocations, later confirmed experimentally.

The comprehensive method for obtaining by Spark Plasma Sintering (SPS) a fine-grained fully dense alumina-based ceramics with a relative density of 99.9%.

SEM - images of characteristic elements of the SCMnCr 3 steel surface after spark assisted deposition of the tin bronze coating (a, c - spherical particles; b - sponge-like structure; d - influxes; e - cracks; f - the result of the collision of a liquid drop with the surface; g - pore )

Pressure welding scheme and mechanical properties of welded samples from different combinations of superalloys based on nickel.

Microadditions of yttrium has resulted in a decrease in the average grain size of low-activation austenitic steel. The decrease in the efficiency of dispersion strengthening by carbide particles has led to a slight decrease in the strength properties of the new steel. MC particles are containing Ti, V, Ta and W surrounding Y kernel.

Dispersion strengthening of the γ-phase particles by the γ′-phase particles in shape memory NiFeGa(B) alloys occurs during hot rolling and subsequent annealing. The optimal texture of the annealed crystals with the special microstructure, should contribute to strengthening the material without cracking along the grain boundaries.

The microstructure of heat-resistant dispersion-hardened 12% chromium ferritic-martensitic steel 16Cr12MnWSiVNbB (type EP-823) demonstrates good thermal stability during aging at 450°C for 5000 h. This maintains its strength properties at the initial level.

The informative drawing shows the structure of CrMnCN steel and the features of its deformation behavior at subzero temperatures.

The surface state of the plates to be welded has a significant effect on the strength and fracture energy of copper joints produced by ultrasonic welding.

Schematic diagram of the ECAP installation with simultaneous application of ultrasound: 1 – ultrasonic generator; 2 – converter; 3 – waveguide, 4 – matrix, 5 – punch, 6 – sample.

Our study is the first to demonstrate that lanthanum, even in small quantities, being part of the Al–Ca–La complex eutectics, has a decisive influence on the microstructure formation and mechanical properties of Al–Ca alloys.

Some areas consisting of two layers free of microcracks have been found in the structure of the coatings (Fig. 1). The lower layer - points (3 – 5) contains an increased concentration of Fe (~ 17-47 at.%). The (Fe) concentration in the crystallites of the upper layer (points 6 – 9) does not exceed 5 at.%, which is adequate to its content in crystallites in the areas with microcracks (Fig. 2). The lower layer of a two-layer coating due to its higher ductility acts as a barrier preventing the occurrence of microcracks at a sufficiently high Fe content (more than 14 wt.%).

A comparison of results between high pressure torsion (HPT) experiments with transformation the layered Cu-Ta composites into metal matrices one.

Structure of a photoresistor with a film of a polyaniline derivative.Oxidative polymerization of 2-(1-methylbut2-en-1-yl)aniline.

Frequency dependences of Fe films (SAS·HCl) at different times of their formation t (days): 1 – 1 day, 2 – 3 days, 3 – 5 days. Pressure P=104Pa.

Disk-shaped nickel plates processed by high pressure torsion were successfully joined by ultrasonic welding. Welding resulted in the grain growth which is uneven along the cross-sectional height of the welded specimen. The specimens showed a gradient microstructure with a grain size ranging from 3 μm in the lower plate to 6 μm in the upper one, along with a developed substructure, after the process of USW.

Figure shows experimental data on particle growth during isothermal annealing at 1300 °C as a time dependence of the average particle volume. For particles located at different distances from the sample surface, these dependences are approximated by straight lines with close angular coefficients (curves 1 and 2).

The annealing at 700 °C for 50 h leads to noticeable changes of the carbide subsystem of low-activation high manganese austenitic steel. After solution treatment (ST) it causes precipitation of M23C6 particles along the grain boundaries and on the MC particles. Annealing of the cold-rolled (CR) samples leads to the formation of these particles at the microtwin boundaries.

This work shows the influence of the degree of severe deformation on the morphological features of α-phase particles in aged metastable β-titanium alloy Ti-15Mo.

The powder morphology, phase composition and microstructure were thoroughly investigated. The temperature ranges of phase transformations in the powder during heating and cooling have been established

Mechanical alloying of elemental powders and subsequent thermal treatment were applied to synthesize Ti6Co16Si7- and Ti6Ni16Si7- based composites.

Change in microhardness depending on the initial microstructure and processing (thermal cycling and annealings)

Structure and the mechanical behavior of a near-alpha multilayer laminate under impact loading

The powder EP741NP superalloy with the initial ultrafine-grained microstructure after superplastic deformation and a solid-state joint in combination of the EP741NP superalloy and a cast intermetallic VKNA-25 alloy.

The artificial aging did not result in any change in the AK12 alloy's microhardness, whereas T6 treatment led to a uniform increase in microhardness throughout all zones of the sample. There was no significant grain growth observed in the aluminum-based solid solution and silicon particles after these heat treatments.

Structural behavior and hardening of the high-strength aluminum alloy 1965 after isothermal rolling at the temperature of liquid nitrogen with reductions in the range of 30-70% was studied for two pre-quenched conditions - the homogenized ingot and further hot-forged billet. In spite of differences in the initial structure parameters, the structure transformations in both the alloy states under cryorolling were preferably associated with the formation and development of the dislocation-cellular structure of the matrix.

The influence of warm multidirectional isothermal forging on the grain structure and mechanical properties of the high-nitrogen austenitic steel VNS-53-Sh has been studied. It has been shown that the average grain size was reduced to ~ 6 μm after forging compare to initial state due to the formation of small grains at the boundaries of the original grains and fragmentation of them. It promote an increase in strength properties.

Microhardness of the Cu-Al-Cu sample after accumulative HPT before and after annealing (left) and schematic representation of the effect of accumulative HPT and further annealing on the sample (right).

The geometric scheme illustrates changes in size of coordination tetrahedron in ZnSxSe1-x substances diluted by 3d-impurity. Neutron-diffraction characterization of structure instability of ZnSxSe1-x:M (M=3d-ions) solid solutions are presented in the article.

In niobium filaments of the Cu-7.7%Nb composite under cold-drawing beginning from the true strain of 8.5, macrostrains are observed according to the X-ray data, which is confirmed by TEM data, which demonstrate distortions of niobium lattice and formation of partially coherent boundaries (110)Nb || (111)Cu. These macrostrains are anisotropic and higher than those in the Cu-18%Nb composites.

The distribution of microhardness (HV 0.5) and the average amount of γ-, α- and ε-martensite in a sample made of steel Fe-0.02C-18Cr-8Ni after SPDT (a) and the distribution of α-martensite under the ductile static fracture surface of steel after ECAP (b, c)

High-temperature annealing of low-activation chromium-manganese austenitic steel leads to discontinuous precipitation of dispersed M23C6 carbides along grain boundaries, micro- and nanotwin boundaries. At coherent twin boundaries, the growth of particles during annealing is limited by cross-sectional dimensions of the twin plates.

The typical macrostructure of the AK4-1 aluminum alloy with local mixing of the AK12D alloy into it via friction stir processing

The inter-fragment boundary misorientation distributions are close at two temperatures of deformation, except for the high-angle peak associated with the twinning at 0.5Tm (Tm is the melting temperature of copper).

Grain fragmentation in tensile strained copper is orientation dependent

The effect of exposure (30, 60, and 120 min) during the processing in the low-pressure non-self-sustained arc discharge plasma on microstructure and phase composition of the modified surface layers obtained in a Ti-6Al-4V alloy with a preliminary deposited Al coating has been evaluated.

explains the efffects of Ce content on the properties as well as on the formed morphologies and scales.