High-intensity Pulsed Electron Beam Research Articles

Liquid-phase boriding of high-chromium steel

Using the methods of modern physical materials science, structuralphase states and tribological properties of 12Kh18N10T steel, subjected to electroexplosive alloying with titanium and boron and subsequent electron-beam processing in various modes depending on electron beam energy density, exposure pulse duration and their quantity have been analyzed. It has been established that electroexplosive alloying of steel with titanium and boron leads to formation of surface layer with multiphase submicro-nanocrystalline structure, characterized by presence of micropores, microcracks, and microcraters. Complex processing, combining electroexplosive alloying and subsequent irradiation with high-intensity pulsed electron beam, leads to formation of 60 μm thick multiphase submicro-nanocrystalline surface layer. It is shown that phase composition of surface layer of steel is determined by mass ratio of titanium and boron during electroexplosive alloying. Microhardness of modified layer is defined by relative mass fraction of titanium borides in surface layer and can be more than 18 times higher than microhardness of steel in its initial state (before electroexplosive alloying). Modes of complex processing have been determined at which surface layer containing exclusively titanium borides and intermetallic compounds based on titanium and iron is formed. The maximum (approximately 82 % by weight) titanium boride content is observed when steel is processed at regime with the highest mass of boron powder in the sample (mB = 87.5 mg; mTi /mB = 5.202). With decrease in mass of boron powder, relative content of borides in surface layer of steel decreases. It was found that integrated processing of steel is accompanied by sevenfold increase in microhardness of surface layer, wear resistance of steel increases by more than nine times.

Effect of Electron-Beam Treatment on the Structure of Commercial-Purity Titanium Subjected to Fatigue Failure

The fracture surface, the phase composition and the state of the defect substructure of the titanium VT1-0 alloy subjected to preliminary irradiation by a high intensity pulsed electron beam and failed under fatigue loading conditions have been studied. A surface layer with a nanocrystalline multiphase structure is shown to form during fatigue tests of the samples preliminarily annealed in air. The surface layer structure of the samples after irradiation is found to differ substantially from the structure of the unirradiated samples: a 5-μm-thick surface layer, in which the grain volumes have a subgrain structure, forms.

Structure and phase states modification of AL-11SI-2CU alloy processed by ion-plasma jet and pulsed electron beam

In the research the investigations into structure, elemental and phase composition, defect substructure of Al-11Si-2Cu hypoeutectic alloy subjected to processing with ion-plasma jet consisting of titanium and yttrium oxide with subsequent irradiation by high intensity pulsed electron beam with energy density of beam of 25 J/cm2 (two-stage processing) were carried out by methods of scanning and transmission electron diffraction microscopy, micro-X-ray spectral analysis. It has been found that structure of Al-11Si-2Cu alloy in cast state demonstrates a polyphase morphologically varied character of the material. Microcraters, solid aluminium-based compounds, intermetallide and eutectic compounds are present in it. It has been revealed that two-stage processing of Al-11Si-2Cu alloy results in cardinal transformation of samples' surface layer structure and it is manifested in dissolution of silicon inclusions and intermetallides of micron and submicro dimensions typical of Al-11Si-2Cu cast alloy. It has been detected that ion-plasma jet effect on alloy surface is accompanied by both alloying of surface layer by plasma elements and penetration of initial powder particles of yttrium oxide. Along with atoms of initial material (Al, Si, Cu, Ni, Fe) the surface layer is enriched by atoms of titanium, yttrium, oxygen. It has been shown that a multielemental polyphase layer ≈60–70 μm thick having a submicro-nanocrystalline structure is formed as a result of two-stage processing.

Structural-Phase State and Properties of Steel After Plasma-Electron Modification

The results of investigation of phase and elemental compositions, defect substructure states, mechanical and tribological properties of the modified surface of Steel Gr1 are presented. The process of modification consists in plasma spraying of a Ni–Cr–B–Si-based powder coating followed by its irradiation with a high-intensity pulsed electron beam. It is shown that the coating surface formed by plasma spraying contains micro- and macro-pores and is characterized by high relief. A subsequent processing of the modified surface with a highintensity pulsed electron beam of a submillisecond duration in the mode of surface layer melting is accompanied by smoothing of the coating surface, saturation of the surface layer crystal lattice with Ni, Cr, B and Si atoms, formation of submicron cells of dendritic recrystallization, precipitation of nanosized particles of the second phase, and formation of quench structure. When combined, these treatments result in the formation of a hardened layer up to 1500 μm in thickness, whose microhardness and wear resistance by 4.6–6.5 and 4 factors exceed the respective characteristics of the initial steel.

Phase Formation Initiated by Irradiation of the Film (Si) – Substrate (Grade 3 Steel) System with a High-Intensity Pulsed Electron Beam

The physical principles of formation of phase composition and defect substructure of a surface alloy in a low-stability state formed as a result of irradiation of the film (Si) - substrate (Grade 3 steel) system with a high -intensity electron beam are revealed. The formation of a multiphase submicro- and nanocrystalline layer is observed. It is shown that irradiation of metals and alloys with a pulsed electron beam in a regime of the surface-layer melting followed by high-rate crystallization frequently gives rise to the formation of local low-stability regions exhibiting a tendency towards the formation of metastable states up to amorphization of the material. A treatment regime is identified, which allows increasing the material microhardness and wear resistance by about 3 and 7.5 factors, respectively.

Friction and wear behavior of WC/Ni cemented carbide tool material irradiated by high-intensity pulsed electron beam

The friction and wear behavior of high-intensity pulsed electron beam (HIPEB)-irradiated YN13 cemented carbide at energy density of 34 J/cm2 and 10 pulses with pulse frequencies of 1 and 5 Hz were investigated in this work by dry sliding wear test against hardened GCr15 bearing steel at 98 N and 0.47 m/s. Surface characterization was conducted by using scanning electron microscope, surface profilometer, X-ray diffraction and Vickers microhardness tester. The dominant wear mechanisms were identified by the worn surface morphologies. The results indicated that an intense surface remelting and ablation/evaporation was induced by HIPEB irradiation with high pulsed frequency, which resulted in the surface roughening, WC phase transformation and improved tribological properties of the YN13 cemented carbide. The specific wear rate and friction coefficient decreased as pulsed frequency increased. When pulsed frequency increased to 5 Hz, they decreased to 53.5% and 70% for non-irradiated samples. The improvement in wear resistance and the significant friction reduction of irradiated samples with the increase in pulsed frequency should be ascribed to the roughening of surface, the refinement microstructure of remelting, and the decrease in irradiated defect in the remelted layer of irradiated YN13 cemented carbide. The main wear mechanism of irradiated YN13 cemented carbide/GCr15 bearing steel pairs was micro-cutting wear in the initial stage of dry sliding wear and abrasive wear with characteristics of Ni preferential removal and fallout of WC similar to the non-irradiated samples in the stable stage.

Increase in Wear Resistance of the Surface Layers of AK10M2N Silumin at Electron-Beam Treatment

It is established that the electron-beam treatment of AK10M2N silumin by a pulsed electron beam with the specific energy of 35 J/cm2 leads to the increase in the surface layer microhardness from 0.99 up to 1.18 GPa with the simultaneous decrease in the friction coefficient by 1.3 times and in the wear coefficient by 6.6 times. After irradiation, a multilayer gradient structure is formed in the surface layer of the silumin. In the surface layer, there are no inclusions of the second phase, whereas in the deeper transient layer there are primary precipitations of intermetallic phase, which are the centers of aluminum crystallization. It is found that the changes in the mechanical and tribological properties of the silumin surface layers are associated with significant structural transformations, for instance, with the dissolution of silicon and intermetallics during irradiation of material with a high-intensity pulsed electron beam.

Evolution of the Structure and Properties of AK10M2N Silumin under Irradiation with a High-Intensity Pulsed Electron Beam

The structure of cast AK10M2N silumin has been studied by scanning electron microscopy. The results demonstrate that the silumin is a multiphase material containing silicon and intermetallic inclusions. Irradiation of silumin with a high-intensity electron beam has been shown to be accompanied by melting of the surface layer, dissolution of the silicon and intermetallic inclusions, formation of a cellular crystallization structure, and secondary precipitation of submicron- and nanometer-sized second-phase particles. Dispersion of the structure of the surface layer is accompanied by an improvement of the mechanical properties of the silumin.

Influence of irradiation with a high-intensity pulsed electron beam on mechanical properties and structural states of coatings formed by plasma spraying

The purpose of the present studies is to establish the formation patterns of the structure and properties of the surface layer of 060A35 steel modified using a combined method that includes plasma spraying of a powder coating and the subsequent irradiation with an intense pulsed electron beam. Plasma spraying on the surface of a steel powder of the system Ni-Cr-B-Si (PGSR-4 with a fraction of 80-100 μm) was performed on the original installation equipped with two plasma generators. The irradiation of the modified steel layer was carried out with an intense pulsed electron beam on the installation SOLO. The investigation of the phase and elemental composition, the state of the defective substructure were carried out using methods of X-ray phase analysis, optical and scanning electron microscopy. The mechanical properties of the irradiated surface were characterized by microhardness. It is shown that plasma spraying of a powder coating leads to formation of a high-relief surface containing micro- and macropores. The subsequent treatment of the modified surface with an intense pulsed electron beam of a submillisecond duration in the melting mode of the surface layer is accompanied by smoothing of the coating surface, saturation of the crystalline lattice of the surface layer with Ni, Cr, B and Si atoms, formation of dendritic crystallization cells of submicron sizes, release of nanoscale particles of the second phase, formation of a quenching structure. Together, this has allowed to increase the microhardness of the modified layer in 4.6-6.5 times.

Tungsten carbide phase transformation under non-equilibrium solidification of high intensity pulsed ion and electron beams

The WC-13Ni cemented carbides irradiated by high-intensity pulsed ion beam (HIPIB, 300 keV, 2–6 J/cm2, 70 ns) and high-intensity pulsed electron beam (HIPEB, 127 keV, 3–34 J/cm2, 180 ns) have been investigated by using scanning electron microscopy, surface profilometer and X-ray diffraction in order to explore the mechanisms of phase transformation. It was found that in both cases beams irradiation with higher energy density resulted in obvious surface remelting and phase transformation from WC to WC1-x, expect that W2C was also found for HIPEB-irradiated samples. However, surface morphology differed greatly in the two cases, HIPIB irradiation induced significant selective ablation of nickel binder, forming a wavy surface of “hill-valley” topography, whereas HIPEB irradiation caused notable surface melting but with less selective ablation, forming a flatter surface with occurrence of apparent cracks and blow holes. The formation of WC1-x phase during the process of beams irradiation should be attributed to the reaction ablation of carbon in the WC and the eutectic reaction at ∼2995 K, while the formation of W2C phase was resulted from the eutectic reaction at ∼2925 K and WC1-x decomposition during the more longer melting process of HIPEB irradiation.

Microstructure and wear properties of Hardox 450 steel surface modified by Fe-C-Cr-Nb-W powder wire surfacing and electron beam treatment

Structural phase states and tribological properties of the coating surfaced onto Hardox 450 martensite low-carbon steel with powder wire Fe-C-Cr-Nb-W and modified by subsequent electron-beam processing are studied by methods of modern physical material science. It is shown that irradiation of ∼ 5 mm thick surfaced layer with high intensity pulsed electron beams results in the formation of ∼ 20 μm thick surface layer with the master phases of α-Fe and NbC, Fe3C and M6C(Fe3W3C) carbides. It is established that wear resistance of the surfaced layer after electron-beam processing increases more than 70-fold relative to wear resistance of Hardox 450 steel and friction coefficient decreases significantly (∼3-fold).

Electron-beam modification of a surface layer deposited on low-carbon steel by means of arc spraying

State-of-the-art means of physical materials science are used to study the structure, phase composition, defect substructure, and tribological properties of a coating formed on low-carbon Hardox 450 martensite steel via the electrocontact deposition of an Fe–C–Ni–B wire and modified through subsequent irradiation with high-intensity pulsed electron beams. It is shown that electron-beam treatment results in the formation of a modified 50-μm thick surface layer, the main phases of which are the α-phase, iron boride FeB, and boron carbide B4C. In the layer modified by electron-beam treatment, the transverse size of batch martensite crystals is reduced by a factor of 3, relative to the initial Hardox 450 steel, and ranges from 50 to 70 nm. It is established that the wear resistance of the deposited layer after electron-beam treatment grows by more than 20 times with respect to the wear resistance of Hardox 450 steel, and the friction coefficient is reduced by a factor of 3.5. The microhardness of a deposited layer ~7 mm thick is more than double that of the base metal.

Dry Sliding Wear Mechanism of WC–13Ni Hard Alloy Irradiated by High-Intensity Pulsed Electron Beam

The wear properties and wear mechanism of WC–13%Ni hard alloy irradiated by high-intensity pulsed electron beam (HIPEB) at energy density of 34 J/cm2 with pulse numbers of 1–10 were investigated by dry sliding wear tests. The phase structure, cross-sectional microstructure and microhardness-depth profiles of the irradiated WC–13Ni hard alloy were examined by using X-ray diffractometer, scanning electron microscopy and Vickers testers, respectively. It was found that HIPEB irradiation induced surface remelting and preferentially ablation of Ni binder phase, resulting in the formation of a modified layer composed of remelted top layer accompany with WC phase transformation and graphite phase precipitation, and shock hardening layer. The specific wear rate of the irradiated samples decreased with the increasing pulse number and reached a minimum value of 3.8 × 10−7 mm3/N m with 10 pulses, only for 32% of the non-irradiated samples. The wear mechanism of surface remelting top layer on the irradiated samples was a homogenous microabrasion wear, which was attributed to the surface remelting and phase transformation, and the wear of the shock hardening layer involved preferential removal of Ni binder phase and detachment of WC grains, but it was restrained by strengthening of Ni binder phase from the deep hardening of HIPEB irradiation.

Structural phase states and properties of the layer surfaced on low-carbon steel with Fe‒C‒Cr‒Nb‒W powder-core wire followed by electron-beam processing

Structural phase states and tribological properties of the coating surfaced onto Hardox 450 martensite low-carbon steel with powder wire Fe‒C‒Cr‒Nb‒W and modified by subsequent electron-beam processing are studied by methods of modern physical material science. It is shown that irradiation of ~5 thick surfaced layer with high intensity pulsed electron beams results in the formation of ~20 μm thick surface layer with the master phases of α-Fe and NbC, Fe3C and M6C(Fe3W3C) carbides. The main difference of the surface layer modified with electron-beam processing from the unmodified volume of the surfacing is the morphology and dimensions of the second phase inclusions. In the modified layer of the surfacing the inclusions have smaller dimensions and are located in the form of interlayers along the grain boundaries. In unmodified surfacing the particles of the faceted shape located chaotically in the grain volume are the basic morphological type of the inclusions. It is noted that the small value of crystal lattice Nb parameter observed in the experiment may be caused by the high level of vacant interstitial sites having the smaller size in comparison with the occupied interstitial sites. It is established that wear resistance of the surfaced layer after electron-beam processing increases more than 70-fold relative to wear resistance of Hardox 450 steel and friction coefficient decreases significantly (~3-fold).

Surface Alloying of SUS 321 Chromium-Nickel Steel by an Electron-Plasma Process

The mechanisms of forming nanostructured, nanophase layers are revealed and analyzed in austenitic steel subjected to surface alloying using an electron-plasma process. Nanostructured, nanophase layers up to 30 μm in thickness were formed by melting of the film/substrate system with an electron beam generated by a SOLO facility (Institute of High Current Electronics, SB RAS), Tomsk), which ensured crystallization and subsequent quenching at the cooling rates within the range 105–108 K/s. The surface was modified with structural stainless steel specimens (SUS 321 steel). The film/substrate system (film thickness 0.5 μm) was formed by a plasma-assisted vacuum-arc process by evaporating a cathode made from a sintered pseudoalloy of the following composition: Zr – 6 at.% Ti – 6 at.% Cu. The film deposition was performed in a QUINTA facility equipped with a PINK hot-cathode plasma source and DI-100 arc evaporators with accelerated cooling of the process cathode, which allowed reducing the size and fraction of the droplet phase in the deposited film. It is found that melting of the film/substrate system (Zr–Ti–Cu)/(SUS 321 steel) using a high-intensity pulsed electron beam followed by the high-rate crystallization is accompanied by the formation of α-iron cellular crystallization structure and precipitation of Cr2Zr, Cr3С2 and TiC particles on the cell boundaries, which as a whole allowed increasing microhardness by a factor of 1.3, Young’s modulus – by a factor of 1.2, wear resistance – by a factor of 2.7, while achieving a three-fold reduction in the friction coefficient.

Study of linearity of LYSO crystal for the high energy cosmic radiation detection (HERD) facility

The high energy cosmic-radiation detection (HERD) facility is a space mission designed for detecting cosmic ray (CR) electrons, $$\gamma $$ -rays up to tens of TeV and CR nuclei from proton to iron up to several PeV. The main instrument of HERD is a 3-D imaging calorimeter (CALO) composed of nearly ten thousand lutetium yttrium orthosilicate (LYSO, with cerium doping) crystal cubes. A large dynamic range of single HERD CALO Cell (HCC) is necessary to achieve HERD’s PeV observation objectives, which means that the response of HCC should maintain a good linearity from minimum ionizing particle (MIP) calibration to PeV shower maximum. In order to study the linearity of HCC over such a large energy range, a beam test has been implemented at the E2 and E3 beam lines of BEPC. High intensity pulsed electron beam provided by E2 line is used for producing high energy density within HCC; $$\pi ^{+}$$ /proton provided by E3 line are used for HCC calibration. The results show that no saturation effect occurs and the linearity of HCC is better than 10% from 30 MeV (1 MIP) to $$1.1\times 10^{3}$$ TeV (energy density is 93 TeV/cm $$^{3})$$ , which can meet the requirement mentioned above.

Structural and Phase Changes in the System Al-Si-Ti-B, Synthesized Using the Electron-Ion-Plasma Treatment Method

The results of surface modification of silumin samples of the eutectic composition using the combined method, which includes the irradiation with plasma formed during an electric explosion of the conductive material and the subsequent processing with a high-intensity pulsed electron beam, are presented. Formation of a multilayer multiphase submicron and nanoscale structure with high mechanical and tribological properties is established. The results of the structural phase analysis of the material are discussed from the standpoint of thermodynamics.

Electron-ion-plasma modification of the structure and properties of commercial steels

AnnotationThe work is devoted to the structural-phase analysis of steels of the austenitic and martensitic grade, irradiated with a high-intensity pulsed electron beam of the submillisecond duration of exposure in the mode of the surface layer melting. A thermodynamic analysis of phase transformations occurring during heat treatment in alloys of the composition Fe-Cr-C and Fe-Cr-Ni-C, which are the basis of steels 20X13 and 12X18H10T, is carried out. It is shown that formation of solid solutions on the basis of α-iron (BCC crystalline lattice) and γ- iron (FCC crystalline lattice) as well as the entire range of carbide phases of a complex elemental composition (M23C6, M7C3 и M3C, where symbol M refers to atoms of metallic elements Fe, Cr, and Ni) is possible in equilibrium conditions in given materials. The irradiation of steels 12X18H10T and 20X13 with a high-intensity pulsed electron beam of the submillisecond duration of exposure is carried out. It is shown that the electron-beam processing of steel in the melting mode and the subsequent rapid crystallization is accompanied by a significant transformation of the surface layer structure, consisting in complete dissolution of original carbide phase particles; in formation of dendritic crystallization cells of submicron sizes; in occurrence of martensitic γ→α and γ→ϵ transformation; in re-allocation of nanosized particles of carbide and intermetallic phases.

Surface characterization and tribological properties of WC-Ni cemented carbide irradiated by high intensity pulsed electron beam

Surface characterization of WC-13Ni cemented carbide irradiated by high intensity pulsed electron beam (HIPEB) at energy density of 3–34 J/cm2 with 10 pulse was investigated by using scanning electron microscope (SEM), X-ray diffraction (XRD), electron probe microanalysis (EPMA) and Vickers tester. The surface tribological properties were measured by a block-on-ring tribometer. It was found that the HIPEB irradiation induced surface remelting and Ni selective ablation, resulting in the phase transformation from hexagonal α-WC to metastable phases, i.e. face centered cubic β-WC1-x and hexagonal α-W2C, and the formation of some defects such as microcracks and blow holes, and then the microstructural changes provided hardening and softening in different degree on the irradiated surface. The friction coefficient of irradiated samples reduced from 0.8 of the original WC-13Ni cemented carbide to 0.5, and the specific wear rate decreased to 3.8 × 10−7 mm3/Nm from 1.2 × 10−6 mm3/Nm, showing the surface tribological properties of HIPEB irradiated WC-13Ni cemented carbide is not only related to the surface hardening, but also with the surface microstructure.

Increase of Fatigue Life of Titanium VT1-0 after Electron Beam Treatment

The processing of commercially pure titanium VT1-0 with high intensity pulsed electron beam was carried out and the mode of irradiation allowing the increase in fatigue life of the material was revealed. Structure investigations of modified layer and fracture surface of commercially pure titanium samples subjected to fatigue multicycle tests were implemented. By methods of scanning electron microscopy the structural transformations responsible for increase in fatigue life of titanium irradiated with high intensity pulsed electron beam were revealed. It was shown that irradiation of commercially pure titanium of grade VT1-0 with high intensity electron beam (25 J/cm2, 150 μs, 3 pulses) resulted in the refinement of grain structure, formation of multilayer structure. Irradiation facilitated the formation of additional structural levels of micro and nanosize range in surface layer.