Metal Science and Heat Treatment

doi: 10.1007/s11041-022-00773-2pmid: N/A

Kolbasnikov, N. G.; Kuzin, S. A.; Teteryatnikov, V. S.; Adigamov, R. R.; Sakharov, M. S.; Matveev, M. A.

doi: 10.1007/s11041-022-00774-1pmid: N/A

Results of experimental and theoretical studies are used to extend understanding of thermal and deformation stability of untransformed austenite in the martensitic-austenitic (MA) component of low-carbon steel bainitic structure. Analysis of the effect of compressive hydrostatic stresses developing during dilatation on austenite stabilization makes it possible to obtain relationships for determining the temperature of the start of martensitic transformation in the MA-component as a function of its volume fraction in the steel structure in order to find the level of deformation due to strain-induced martensitic transformation.

Pal, Vinay Kumar; Singh, L. P.; Tariq, M.

doi: 10.1007/s11041-022-00775-0pmid: N/A

The effect of normalizing in the temperature range 950 – 1150°C with subsequent tempering for 2 h at 760°C on the microstructure of Cr – Mo steel P92 is studied by optical and electron microscopy. The interconnection between steel microstructure and mechanical properties is considered. Normalizing at 1040°C is shown to be advantageous for forming a fine-grained structure containing tempered martensite and strengthening inclusions with favorable morphology and composition.

Petrova, A. O.; Popov, A. A.; Popov, N. A.; Narygina, I. V.; Korelin, A. V.

doi: 10.1007/s11041-022-00776-zpmid: N/A

Precipitation of secondary phases in quenched alloy Ti – 14% Mo during continuous heating at a rate of 5 K/min is studied. Using quantitative methods of analytical transmission electron microscopy and x-ray structural phase analysis in situ presence within the alloy of athermal ω-phase is established, quenched from the β-range, whose lattice constants differ somewhat from the tabulated values. On heating there is precipitation of isothermal ω-phase with spacings approximating tabulated values, and at temperatures above 500°C there is formation of α-phase particles within the alloy structure. The effect of precipitated second phases particles on alloy hardness is determined.

Roy, Utpal Kumar; Mondal, Subrata

doi: 10.1007/s11041-022-00777-ypmid: N/A

The structure and properties of powder composites with an aluminum matrix reinforced with carbon materials of two types, i.e., nanotubes (CNT) and nanofibers (CNF), in an amount of 0.5 – 1.5 wt.% are studied. Composite microstructure is analyzed using optical and scanning electron microscopy. It is shown that hardness, compressive strength, and wear resistance of the nanocomposites increase with weight CNT and CNF fraction due to grain refinement and uniform nanoparticle distribution within the matrix. Reinforcement with CNT is more effective.

Hamza, Mohammad; Mondal, Subrata

doi: 10.1007/s11041-022-00778-xpmid: N/A

The effect of reinforcement with ceramic microparticles of SiC, B4C and Al2O3 on the microstructure and mechanical properties of composite materials with an aluminum matrix produced by powder metallurgy is studied. It is shown that an increase in reinforcing particle concentration gives rise to a substantial increase in composite compressive strength and hardness with an insignificant increase in density. The connection of microstructure morphology with composites properties is demonstrated.

Kovtunov, A. I.; Khokhlov, Yu. Yu.; Myamin, S. V.

doi: 10.1007/s11041-022-00779-wpmid: N/A

Liquid-phase technology for fabricating composite materials with a magnesium matrix and titanium reinforcement is proposed. Possibilities of improving adhesive bonding between composite components under casting conditions with preliminary deposition of an aluminum layer on titanium reinforcement and process activation with chloride-fluoride fluxes are considered. Cohesive strength between magnesium and titanium within composites is determined. Tensile tests of composite material specimens are performed and metallographic and x-ray spectrum analyses are conducted. The most effective activating flux compositions are proposed after analyzing composite material structure. Mechanical property tests for composites prove the efficiency of reinforcing a magnesium matrix with titanium.

Karabas, Muhammet

doi: 10.1007/s11041-022-00780-3pmid: N/A

Methods of electron microscopy and x-ray diffractometry are used to study the structure of a titanium coating deposited on a magnesium substrate by high-velocity oxy-fuel spraying. The coating is tested for corrosion resistance in an SBF environment modeling biological fluid. The coating has a low porosity and contains some oxide phase, and there is diffusion at the coating substrate interface. It is shown that a titanium coating reduces magnesium substrate corrosion rate considerably. Presence of Ca and P at the surface facilitates formation of bone tissue within an SBF medium.

Ucar, N.; Ekinci, C.; Calik, A.; Keddam, M.

doi: 10.1007/s11041-022-00781-2pmid: N/A

The kinetics of boriding of Fe – Ni alloys containing 60, 70, 80, and 90 wt.% Ni at 1073 – 1373 K for 2 – 8 h in powdered mixtures with the use of Ekabor-3 boriding agent has been investigated. It has been established that a compact multiphase layer represented by nickel silicides, borosilicides, and borides is formed on the alloy surface. The hardness of the layer depends on the nickel concentration in the substrate. It is shown that the growth of the boride layer with time can be described by a parabolic dependence. The activation energy of the boron diffusion in Fe – Ni alloys is also a function of the nickel content.

Talis, A. L.; Everstov, A. A.; Kraposhin, V. S.

doi: 10.1007/s11041-022-00792-zpmid: N/A

The article considers linear substructures of close-packed metals represented by helical packings of universal building units (tetrablocks) united over faces, i.e. seven-vertex unions of four tetrahedra over faces. The implementation of such helical packings is demonstrated for cubic crystals of α- and β-manganese as an example.