Increase in the fatigue durability of stainless steel by electron-beam surface treatment

The structure, phase composition and dislocation substructure of 20Cr23Ni18 steel subjected to electron-beam treatment and subsequent multicycle fatigue loading until destruction were studied by scanning and transmission electron microscopy. It was shown that electron-beam treatment with an energy density of 20 J/cm² increases the fatigue durability by a factor of 2.1. The cause of steel fatigue destruction is analyzed and a way of further increasing the fatigue durability is proposed.     

不锈钢电子束收集极的损伤能量密度阈值

对强磁场相对论返波管系统中电子束收集极损伤的主要影响因素进行了分析,通过设计并使用锥面不锈钢收集极,提高了收集极的耐电子束轰击能力。在单次实验条件下,研究了电子束能量密度对不锈钢收集极表面损伤及系统产生微波的影响,结合对无箔二极管中电子束空间密度分布的研究结果,给出了不锈钢收集极损伤电子束能量密度阈值范围。     

Problems in initiating detonation of disruptive explosives by a high-intensity electron beam

Experiments on initiating detonation in disruptive explosives by a nanosecond high-intensity electron beam are considered. It is shown using elementary computational estimates that the critical conditions for initiating detonation in a disruptive explosive are not satisfied for the beam parameters described here. The results of experiments on the action of a pulsed electron beam on paraffin and wax model samples are considered. It is shown that the main factor acting on the samples is the cathode plasma torch.     

Structure and properties of the surface alloy formed by irradiating a film/substrate system with a high-intensity electron beam

A film/substrate system has been treated with a submillisecond high-intensity electron beam. Examinations have shown that the electron-beam treatment of the film/substrate system resulted in alloying of the surface layer of the material throughout the melt which was accompanied by the formation of nanodimensional phases.     

Microstructure evolution occurring in the modified surface of 316L stainless steel under high current pulsed electron beam treatment

High current pulsed electron beam (HCPEB) surface treatment of 316L stainless steel (SS) was carried out with a wide spectrum of treating parameters. Microstructure changes occurring in the modified surface were characterized with microscopy, X-ray diffractometry and electron backscatter diffractometry (EBSD) techniques. The evolution regularities of surface craters and microstructure refinement, as well as preferred orientation of (1 1 1) crystal planes were discussed on considering the coupled temperature-stress fields formed in surface layers after an absorption of HCPEB energy.     

The effect of nanostructured surface layer on the fatigue behaviors of a carbon steel

A nanostructured surface layer was formed on a carbon steel by means of surface mechanical attrition treatment (SMAT). The microstructure of the surface layer of the SMATed sample was characterized by using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Microhardness and residual stress distribution along the depth from the SMATed surface layer were measured at the same time. Fatigue behaviors of the carbon steel subjected to the SMAT process were investigated. A nanostructured layer with average grains size of ∼12.7 nm was formed, of which microhardness is more than twice as high as that in matrix and residual compressive stress can reach about −400 MPa with maximum depth of ∼600 μm. The fatigue strength of as-received sample is 267 MPa and that of SMATed sample is 302 MPa based on fatigue life 5 × 10⁶ cycles. The SMAT process has improved the fatigue strength by as much as 13.1% for the carbon steel. It is shown that the SMAT is an effective method to render the material with the features, such as a nanostructured and work-hardened surface layer as well as compressive residual stresses, which can pronouncedly improve the fatigue strength of the carbon steel.     

Secondary electron yield from stainless steel surface coated with titanium nitride

The experiment on measurement of secondary electron yield from surface of a stainless steel Kh189 sample covered with titanium nitride is performed at stand “Recuperator”. This work is related to known problem of electron clouds formation in a vacuum chamber by a propagating charge particle beam. An original method of secondary electron yield measurement was developed in this experiment. The obtained results allow one to estimate efficiency of coating nitride titanium.     

Hardening of steel by alloying in a relativistic electron beam

The possibility was demonstrated of hardening a steel surface layer by alloying it using the energy of relativistic electrons. Investigations were made of how the structure, hardness, and depth of the hardened layer depend on the processing regime and on the initial temperature of the steel in the case of alloying with boron carbide and with Cr+C and Cr+B₄C mixtures. The greatest hardening was achieved by alloying with a mixture of Cr and B₄C powders. This was due to a higher volume fraction of the second phase in the layer and to the precipitation of chromium carboborides. Several types of alloying utilizing Cr+B₄C and containing additional agents and modifiers were developed on the basis of the data obtained.Institute of Hardening Physics and Materials Research, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 57–63, March, 1993.     

Formation of the surface layer structure of electron-beam-doped steel

We demonstrate the possibility of strengthening the surface layer of steel through the mechanism of irradiation with a relativistic electron beam by precipitating the high-strength carboboride inclusions in the solid martensitic matrix. The hardness in the processed region depends on its composition and the thickness of the previously deposited powder coating. The introduction of special modifying admixtures significantly reduces in size the structure of the layer.Institute of Strength Physics and Materials Science, Siberian Branch, Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 89–94, April, 1994.     

On the fatigue strength of grade 20Cr13 hardened steel modified by an electron beam

The treatment of 20Cr13-grade hardened steel (0.2% C, 13% Cr) with an electron beam whose energy density is 10–30 J/cm² results in an increase in the fatigue life by a factor of 1.9. The irradiated surface is investigated by scanning electron microscopy; substantial refinement of the grain structure and a change in the Cr content in the surface layer are revealed.     

Wear resistance of laser cladding and plasma spray welding layer on stainless steel surface

The effect of coatings, which are formed with laser cladding and plasma spray welding on 1Cr18Ni9Ti base metal, on wear resistance is studied, A 5-kW transverse flowing CO2 laser is used for cladding Co base alloy powder pre-placed on the substrate. Comparing with the plasma spray coatings, the spoiled rate of products with laser clad layers was lower and the rate of finished products was higher. Their microstructure is extremely fine. They have close texture and small size grain. Their dilution resulting from the compositions of the base metal and thermal effect on base metal are less. The hardness, toughness,and strength of the laser cladding layers are higher. Wear tests show that the laser layers have higher properties of anti-friction, anti-scour and high-temperature sliding strike. The wear resistance of laser clad layers are about one time higher than that of plasma spray welding layer.     

Properties and structural state of the surface layer in a zirconium alloy modified by a pulsed electron beam and saturated by hydrogen

A pulsed action of an electron beam on a Zr-1% Nb zirconium alloy is studied. Alloy samples are irradiated by three 50-μs pulses at an energy density of 15–25 J/cm², a power of (3–6) × 10⁴ W/cm², a current density of 10–50 A/cm², and an electron energy of 18 keV. This method of processing is found to modify the surface layer of the alloy without changing the structure-phase state of its volume. This surface modification increases the hydrogen saturation resistance of the alloy.     

耐酸不锈钢表面激光熔覆层耐腐蚀研究

本文研究了在耐酸不锈钢基体上采用激光熔覆和等离子喷焊二种工艺形成的涂层对耐腐蚀性的影响。使用５ｋＷ横流ＣＯ２激光器对预置在基体上的Ｃｏ基自熔合金粉末进行熔覆加工,得到的熔层与等离子焊层对比：激光熔层缺陷率低,被机体稀释率更小,成品率更高。其组织致密均匀,晶粒细小,熔层硬度与强韧性更高。性能试验证明：激光熔层有更好的耐腐蚀性能。     

Terahertz radiation from interaction between an electron beam and a planar surface plasmon structure

The possibility of an electron beam exciting surface plasmons in conducting metal is discussed in this paper. A planar perfect-structure with subwavelength holes is proposed. The phenomenon that mimicking surface plasmon waves can be excited and amplified by an electron beam is proved theoretically and numerically. The mechanism of transmission through a subwavelength hole array is exploited to enhance the interaction between the electron beam and the mimicking surface plasmons.     

强流脉冲离子束辐照对不锈钢耐腐蚀性能的影响

 利用强流脉冲离子束（HIPIB）对316L不锈钢进行了表面辐照处理,研究了HIPIB辐照对其在0.5mol/L H2SO4溶液中电化学腐蚀性能的影响。极化曲线测量结果表明,HIPIB辐照能够显著提高316L的抗腐蚀性能,自腐蚀电流对辐照次数的依赖性与自腐蚀电位相比明显较强。采用扫描电子显微镜（SEM）、X射线衍射（XRD）和电子探针（EPMA）分析辐照后试样表面形貌、表面层相结构和元素分布的变化。结果表明：HIPIB辐照使试样表面光滑化,表面层产生择优取向,且发生了杂质元素的选择性烧蚀,是316L不锈钢耐电化学腐蚀性能得以提高的主要原因。     

Surface structure of alumina ceramics during irradiation by a pulsed electron beam

The structural transformations that occur in the near-surface layer in alumina ceramics during irradiation by a pulsed electron beam generated by a forevacuum plasma electron source are studied. The modification of the surface properties of the ceramics is shown to be caused by the formation of regions consisting of close-packed and identically oriented crystallites within every grain. The crystallites are elongated: their length and width are 0.5–1.5 μm and the transverse size is 0.1–0.2 μm.     

Nonlinear surface processes under nonequilibrium TiNi activation by a pulsed electron beam

Nonlinear processes involved in oxygen diffusion from the adsorption layer into the bulk of an alloy exposed to a low-energy high-current pulsed electron beam are investigated in the framework of a mathematical model accounting for nonequilibrium activation and melting of the irradiated material. An example is a TiNi alloy. The model includes heat, diffusion, and kinetic equations, with initial and boundary conditions corresponding to electron-beam treatment of the alloy. Kinetic parameters are estimated. The time and space distributions of the TiNi temperature and oxygen concentration for a varying maximum pulse power density and pulse duration are calculated. The heating and diffusion depths are determined. The results obtained with and without regard to the activation effect are compared. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 8–15, March 2007.     

Change of dislocation substructures upon high-cycle fatigue of stainless steel

Methods of transmission electron microscopy of thin foils are used to study the evolution of dislocation substructures in Fe–0.1C–1.7Mn–0.92Ti–18.2Cr–10.4Ni–0.71Si corrosion-proof austenitic steel subject to high-cycle fatigue loading to destruction. Quantitative dependences of the dislocation substructure parameters on the number of loading cycles and distances to the sample surface are established. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 42–45, March, 2009.