Search results

A number of studies [6] are aimed at partial replacement of fine aggregate in concrete mixtures.
The name of indicators Actual indicators Requirements GOST 5578-2019 Partial sieve residue, [%] 10 4,3 – 5 14,8 – 2,5 8,6 – 1,25 14,2 – 0,63 12,4 – 0,315 17,5 – 0,16 15,6 – ˂ 0,16 12,6 – Full sieve residue, [%] 2,5 8,6 – 1,25 22,8 – 0,63 35,2 – 0,315 52,7 – 0,16 68,3 – Grain composition, [%] Size module 1,87 small Total residue on sieve № 063 35,2 I063 =10-30 Grain content over 10 [mm] 4,3 0,5 Grain content over 5 [mm] 19,2 10,0 Grain content less than 0,16 [mm] 12,6 20 Loss on ignition, [%] 1,8 No more 3,0 Content FeO + MnO, [%] 10,9 No more 3 The content of sulfur compounds in terms of SO3, [%] 0,9 No more 4,5 Dust content, [%] 2,2 No more 3 Content of metal inclusions, [%] 0 No more 3 Bulk density in a state of natural moisture, [kg/m3] 1270 – Bulk density in dry condition, [kg/m3] 1365 – True density, [g/cm3] 2,91 – Emptiness in a state of natural moisture, [%] 54,2 – Dry void, [%] 51,8 – Humidity, [%] 3,2 – The physical and mechanical properties of steelmaking slag were studied in
During the research, the moisture content of the molding sand and the grain size distribution of the original SS were varied (Table 7).

The effect of annealing on the structural and electrical properties of copper films has been investigated by a number of workers [5-10].
The appreciable increase in integrated intensity of (111) peak of C3-a in comparison with the C1-a is also an indicative of crystallinity in that orientation due to refinement of grain boundaries.
However, small improvement in grain size was observed after thermal annealing in 50 nm thick sample in argon environment.
The deviation of lattice constant for the deposited thin film over the bulk 3.615 Å clearly suggests that the film grains are strained [14].
The enhancement of the reflectance could be the result of improved microstructure after annealing and the defects in Cu crystalline structure were minimized through annealing and grain boundaries were modified.

The absence of such an operation as transferring products from drying buggies to firing buggies greatly simplifies the technological scheme, reduces the number of machines and significantly reduces the technological costs.
As a result of processing, various associated materials are formed, which are classified by the grain composition, amount of coal component and mineralogical-petrographic composition [7-9].   4 groups of materials are distinguished by the grain composition: – large (L) – with a fractional composition from 5 mm to 150 mm; – medium (M) – with a fractional composition from 2 to 5 mm; – small (S) – with a fractional composition from 0.5 to 2 mm; – thin (T) – with a fractional composition from 0 to 0.5 mm.
If the coarse grain materials are widely used in civil, industrial and road construction, and small and thin materials as low-grade fuel, the screenings are the least popular.
The dependence of the raw materials’ plasticity on the content siliceous clay and the grain size screenings Fig. 2.
The dependence of the raw materials’ connectivity on the content siliceous clay and the grain size screenings The introduction of a siliceous additive has a noticeable effect on the strength of calcined samples only at elevated firing temperatures - higher 1000 о С.

Even after casting 1570 alloy ingots have grain microstructure (grain size of about 40 μm) and homogenization process should be considered from prospective of dissolution of large (> 1 μm) Al-based intermetallic compounds containing Mg (β-phase), adjustment of alloying components (Mn, Mg) concentration based on grain section and coagulation of hardly soluble iron-manganese Al(MnFe) intermetallic compounds (see fig. 1).
Mechanical properties of the samples produced along the route number: а) 1 b) 2.
The sheets produced using the practice, including final stabilizing annealing, have fibrous structure with β-phase precipitates along the grain boundaries in the form of continuous chains, making sheets susceptible to layer corrosion and thus cannot be recommended for application for the structures exposed to aggressive environments such as sea water.
Thus, to obtain the H321 temper in 1570 alloy sheets, a revision of the traditional practice is required, consisting in the increase of work-hardening degree before annealing, or in annealing temperature decrease. 1570 alloy sheets, work-hardened to a quarter of strength, have higher mechanical properties and, at the same time, due to the absence of continuous chains of intermetallic compounds along the grain boundaries, they meet both international standards and Russian regulations requirements for the products exposed to marine environment.

The oriented nucleation enhances the film quality in future growth by reducing the grain boundary area considerably.
The ZnO seed B that was deposited at room temperature was partly amorphous and contained a large number of crystallite grains.
The surface free energy is not the only factor causing grain preferential growth in the film, as has been widely discussed [11, 12].
Several factors have been reported to influence preferential growth in a polycrystalline film, including nucleation, precursor atom sticking probability, surface diffusion, grain growth, and post-growth treatments of the film. [11, 12].
The conductivity can be improved by increased in donors, improved crystallinity and decrease the grain boundary scattering[19].

In Zn-Al-Cu alloys copper with zinc forms a solid solution crystallizes in the wall centered (fcc), regular system for the coordination number k = 12.
It is easier to remove atoms less bounded with neighbours (with a lower coordination number).
For the metal surface exposed to the corrosive environment on the corrosion resistance of each grain varies due to differences in the binding energy between the atoms in the crystal lattice.
Grain boundaries are places of increased internal energy that determines their lower resistance to corrosive environments.
Fine-grained structure disadvantageously influences on resistance to electrochemical corrosion.

a) b) c) Journal Title and Volume Number (to be inserted by the publisher) 3 Investigated components and experimental procedure Tested were commercial PZT based multilayer stacks in the size 7x7x30 mm³.
The fracture surface at the left hand side is covered with the metallic layer, which contains holes and shows traces of the ceramic grain structure.
P P P P Journal Title and Volume Number (to be inserted by the publisher) 5 ceramic.
Also shown is the fracture surface of another specimen in a higher magnification (c), where the grain structure of the PZT polycrystals is visible.
; the grain structure of the PZT poly crystals is clearly visible, at the top of the specimen some plastic deformation resulting from the machining of the specimen can be recognised.

Grains in this layer were apparently flattened and elongated in the axial direction of the specimen, and the grain size significantly decreased.
On the contrary, the shape or size of grains did not change in the core portion of the specimen.
For NHH, the pearlite blocks at the notched part were also Fig.3 Relation between fatigue limits and the deformation values of test materials 10 4 10 5 10 6 10 7 10 8 30 35 40 45 50 55 60 65 70 75 80 Stress amplitude σ, MPa Number of cycles to failure N, cycles A000 A015 A025 A035 104 105 106 107 108 0 50 100 150 200 250 300 350 400 450 500 Stress amplitude σ, MPa Number of cycles to failure N, cycles S000 S025 S050 S100 S150 104 105 106 107 108 0 100 200 300 400 500 600 Stress amplitude σ, MPa Number of cycles to failure N, cycles N000 N005 N010 N015 N025 (a) AL1050 (b) S25C (c) NHH Fig.4 Microstructure of notch bottom with roller working (a) AL1050 (b) S25C (c) NHH 200µm 400µm 200µm elongated in the axial direction and the depths of work hardening layer of N005, N010, N015 and N025 were about 200, 280, 360 and 400µm, respectively.

Introduction High heating and cooling rates attainable in laser cladding process give rise to extremely fine-grained microstructures and excellent mechanical properties in the coatings.
Liu et al [3], it was found that among the three compositions of cladding layer, Ni21+20%WC+0.5%CeO2 cladding layer was made up of finer grains, and presented the best abrasion wear behavior at high temperature.
Furthermore, more nucleation sights by powder particles, which may not be completely molten near the surface, locally affect the number of nucleation sites.
It is found that the microstructure of the coating consists of a large number of white particles dispersed within dendrite and interdendritic regions.
First, a number of ceramic particles with high hardness and thermodynamic stability are uniformly dispersed in the matrixes, which improve the bonding strength between the particles and the Ni-based matrix.

In the course of studying a number of Alnico and 25Cr15Co samples by means of SEM, data were obtained that testify to the uneven distribution of the chemical composition over the surface of thin sections of the samples of these alloys (Fig. 2b).
The experiments showed that an increase in laser power up to 195 W is accompanied by an improvement in the metallurgical quality of the additive metal with a small number of discontinuities, which does not contradict other works devoted to additive technologies [17-19].
The presence of oxides in the background of crushed grain is a factor in the hardening of the additive metal.
At the same time, the SLM technology made it possible to obtain a finer grain structure, which suggests that it seems possible to obtain even more satisfactory properties.
The excess of hardness indicators can be associated with the features of the SLM process, namely, the formation of a finer-grained structure as a result of laser exposure, as well as with the previously indicated oxide deposition.