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Study on laser cladding and properties of AZ63-Er alloy for automobile engine
摘要： Aiming at the problem of the poor corrosion resistance of magnesium alloys for automobiles, Al-TiC and Al-TiC-Y2O3 cladding layers were prepared on the AZ63-Er alloy by laser cladding technology, studied the effects of Al:TiC mass ratio and Y2O3 addition on the microstructure, phase composition, hardness and corrosion resistance of the cladding layer. The results show that the Al-TiC laser cladding layer with different mass ratios has metallurgical bonding with AZ63-Er alloy substrate, and there are no pores or cracks at the interface. The main phases of the Al-TiC laser cladding layer are Ti3AlC, TiC, Mg2Al3, Al3Mg2, Al, Mg, AlMg and Ti6O. The hardness of laser cladding layer with the mass ratios of Al:TiC are 8:1, 4:1 and 2:1 are about 2.75, 3.24 and 3.94 times of the substrate. The corrosion resistance of Al-TiC cladding layer is higher than that of the AZ63-Er alloy substrate, and the corrosion resistance of the Al:TiC cladding layer with the mass ratio of 8:1 is the best. Al3Y and Al4MgY phases are formed in the Al-TiC-Y2O3 cladding layer after Y2O3 addition. The hardness of the Al-TiC-Y2O3 cladding layer is significantly higher than that of the Al-TiC cladding layer. The Al-TiC-Y2O3 composite cladding layer has the best hardness and corrosion resistance when the Y2O3 content is 0.6%.
关键词： surface modification,laser cladding,hardness,AZ63-Er alloy,corrosion resistance
更新于2025-09-19 17:13:59
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Influence of Powder Condition on Surface Properties of Cold-Resistant High-Strength Steel Produced by Direct Laser Deposition Method
摘要： Direct laser deposition (DLD) allows creating parts of complex shapes and configurations in a single process step without using of additional equipment. Such technologies are required in the shipbuilding industry, aircrafts, gas turbines, mechanical engineering etc., where it is necessary to manufacture large-sized and complex products that have a long technological cycle for production using classical technologies. DLD makes it possible to produce parts of various alloys with mechanical characteristics at the level of the wrought alloys. The publication is described direct laser deposition of high-strength cold-resistant steels results. Besides mechanical properties of material, the exploitation properties of the structure are also significantly important. Results of corrosion, abrasive-corrosion and tribotechnical tests are shown.
关键词： corrosion resistance,high-strength steel,abrasive-corrosion resistance,Direct laser deposition,cold-resistant steel,initial powder condition,wear resistance
更新于2025-09-16 10:30:52
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Microstructure and selected properties of boronized layers produced on C45 and CT90 steels after modification by diode laser
摘要： The paper presents the study results of macro- and microstructure, microhardness and corrosion resistance of C45 medium carbon steel and CT90 high carbon steel after diffusion boriding and laser modification by diode laser. It was found that the increase of carbon content reduced the thickness of boronized layer and caused change in their morphology. Diffusion boronized layers were composed of FeB and Fe2B iron borides. As a result of laser surface modification of these layers, the microstructure composed of three areas: remelted zone, heat affected zone (HAZ) and the substrate was obtained. Microhardness of laser remelting boronized layer in comparison with diffusion boronized layer was lower. The presence of HAZ was advantageous, because mild microhardness gradient between the layer and the substrate was assured. The specimens with laser boronized layers were characterized by better corrosion resistance than specimens without modified layer.
关键词： Laser remelting,Boronized layer,Corrosion resistance,Microstructure,Microhardness
更新于2025-09-16 10:30:52
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The microstructure and oxidation behavior of the N-doped modified layers on uranium surface prepared by pulsed laser irradiating
摘要： The N-doped modi?ed layer on uranium surface was prepared by pulsed laser irradiating in nitrogen atmosphere. The results of microstructure characterised by XRD, AES and XPS show that it is a composite layer with a gradual transition structure from UO2-xNy and uranium oxy-nitride (UNxOy) to UN and eventually to uranium from surface to interior. Initial oxidation behavior after sputtering for di?erent time illustrates that UNxOy with U 4f7/2 BE at 379.6 eV is inert under oxygen exposure. Further, the thermal stability study shows that the modi?ed layer exhibits excellent ability to prevent the O atoms from di?using into the interior at 423 K. Moreover, the corrosion protective properties of the N-doped modi?ed layers before and after thermal treatment were evaluated through potentiodynamic polarization tests. The results show that the N-doped modi?ed layer improved the corrosion protective properties of metallic uranium. The self-corrosive potential and self-corrosive current of the N-doped modi?ed layer are ?5.75 × 10?2 V vs. SCE and 1.37 × 10?7 A/cm2, while the values of metallic uranium were ?5.67 × 10?1 V vs. SCE and 8.08 × 10?7 A/cm2. After thermal treatment, its values are ?8.57 × 10?2 V vs. SCE and 4.83 × 10?8 A/cm2, indicating that the corrosion resistance of the N-doped modi?ed layer was further improved.
关键词： Corrosion resistance,N-doped modi?ed layer,UNxOy,Microstructure,Pulsed laser irradiating
更新于2025-09-16 10:30:52
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Reducing the pitting susceptibility of AISI 304 stainless steel using a hybrid treatment of high-power diode laser and large pulsed electron beam irradiation
摘要： Large pulsed electron beam (LPEB) irradiation has been widely used for surface modification of metals, alloys, polymers, and composites due to its unique interaction mechanisms with materials. The rapid melting and resolidification processes during LPEB irradiation induce phase transformation at the resolidified layer, which enables a simultaneous improvement in mechanical characteristics and chemical stability of metals. However, the generation of craters during LPEB irradiation adversely affects surface quality. It is imperative to minimize crater formation following LPEB irradiation to mitigate pitting corrosion on the surface of stainless steel (SS). In this study, a hybrid surface modification approach using a high-power diode laser (HPDL) and LPEB is proposed to reduce the crater generation during LPEB irradiation. The size and density of craters generated during LPEB irradiation were effectively reduced following the HPDL-LPEB irradiation hybrid surface treatment. The decrease in extent of crater formation and phase transformation has enabled an improvement in corrosion resistance. The ability of the resolidified layer formed after the hybrid HPDL-LPEB irradiation to form a stable passive film shifts the pitting potential from less than 0 mV/SCE (for untreated 304 SS) to more than +800 mV/SCE, which reduced the depth of corroded pits by 75%. The hybrid HPDL-LPEB irradiation decreased non-metallic inclusions, extent of crater formation and the surface roughness, and improved the pitting corrosion and general corrosion resistance.
关键词： High power diode laser,Pitting corrosion,Electron beam,Microstructure,Corrosion resistance,Stainless steels
更新于2025-09-12 10:27:22
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Effect of energy parameters of pulsed laser welding of Zr-1%Nb alloy on metal contamination with gases and properties of welds
摘要： Effect of pulsed laser welding parameters (pulse energy and duration, frequency, welding speed and, as a result, overlapping factor) on properties of E110 (Zr-1%Nb) alloy welds is presented. Butt welded joints of two identical plates with a thickness of 0.5 mm were investigated. EDS analysis of a surface layer of the welds was done, initial hydrogen concentration in the weld metal was measured and influence of absorbed gases (oxygen, nitrogen, carbon and hydrogen) on tensile strength, microhardness, hydrogen absorption rate and corrosion resistance of the welds was evaluated. The weld metal contained initial hydrogen concentration within the limits set by standards. However, mixing argon flows with atmospheric gases caused the weld metal contamination with oxygen, nitrogen and carbon. As a result, inclusions of complex chemical composition and surface branching microcracks were formed. They were stress raisers where weld failures occurred. Furthermore, it was the reason of increased hydrogen absorption rate and decreased corrosion resistance of the weld metal. The obtained results showed that absence of discoloration on surfaces of the welded joints did not guarantee metal purity and, as a consequence, required performance properties. Future research is required to determine the optimal overlapping factor; shielding gas compositions (Ar, He or their mixture) and flow rates; configuration and inclination angle of nozzles as well as distance from the nozzles to the weld zone.
关键词： Pulsed laser welding,Metal contamination,Corrosion resistance,Hydrogen content,Zirconium alloy,Hydrogen absorption rate
更新于2025-09-12 10:27:22
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Efficient Interfacial Solar Steam Generator with Controlled Macromorphology Derived from Flour via “Dough Figurine” Technology
摘要： Poor corrosion and wear resistance of magnesium (Mg) alloys restrict their applications. Herein, corrosion and wear-resistant films are formed upon Mg alloy AZ31 through a micro-arc oxidation (MAO) process in silicate electrolyte in the presence of carbon spheres (CS). Surface morphology, chemical composition, corrosion resistance, hardness, and coefficient of friction (CoF) of the MAO coatings are investigated using field-emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectrometry (FTIR), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), electrochemical and hydrogen evolution measurements, automatic micro-hardness testing, and reciprocating tribometer, respectively. Results demonstrate that the surface morphology and hardness of MAO coatings vary with the concentration of CS. The presence of CS results in an increased coating thickness from 8.0 (cid:1) 1.8 to 12.2 (cid:1) 1.8 μm, mean pore size from 0.7 (cid:1) 0.1 to 1.9 (cid:1) 0.1 μm, open porosity of MAO coating from 4.2 (cid:1) 0.4 to 5.6% (cid:1) 1.1%, and coating hardness from 347.0 (cid:1) 59.0 to 853.0 (cid:1) 67.3 Vickers-hardness (HV). Furthermore, CS-modified MAO coatings lead to improved corrosion resistance in comparison with that of the neat MAO counterparts. Moreover, the high hardness and formation of SiC of CS-modified coatings lead to a low and stabilized CoF, which implies an enhanced wear resistance.
关键词： micro-arc oxidation,coatings,corrosion resistance,carbon spheres,magnesium alloys
更新于2025-09-11 14:15:04
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Light Metals 2016 (TMS/Light) || SiC in Electrolysis Pots: An Update
摘要： This update reviews recent results of physical and chemical testing of Si3N4-bonded SiC sidelining material for aluminium electrolysis pots, as well as the corrosion mechanisms of SiC materials under electrolysis conditions. New test methods have been developed to show how these materials perform in a harsh operating environment. The attack by low temperature bath was tested on SiC bricks, also with SiAlON and N-SiC as binder phase. Reverse reactive sintering has become an important manufacturing process for Si3N4-bonded SiC sidelining material This review updates [1, 2].
关键词： SiC corrosion resistance,SiC manufacture,SiC degradation
更新于2025-09-10 09:29:36
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Surface micro-structuring of type 304 stainless steel by femtosecond pulsed laser: effect on surface wettability and corrosion resistance
摘要： This paper presents results on femtosecond (fs) pulsed laser-based surface micro-structuring of type 304 stainless steel (304 SS). Post laser treatment surface wettability and corrosion resistance investigation are reported. SS sample surfaces have been micro-structured using a typical laser fluence of ~ 0.9 J/cm2 for varying sample scanning speed in the range 25–1000 μm/s. Dense array of micro-protrusions have been generated without formation of a crater for an optimized target scan speed exceeding 200 μm/s. Static water contact angle (WCA) measurement indicated super-hydrophilic behavior immediately after laser treatment. However, hydrophilicity (wettability) was found to decrease with storage time with sample becoming highly hydrophobic (WCA: 144° ± 5°) within 50 days after laser treatment. Corrosion resistance of the laser-treated samples was measured by potentio-dynamic polarization technique. Fs laser micro-structured SS has shown poorer corrosion resistance in comparison to pristine surface. Observed poorer corrosion resistance of laser-treated surface has been explained on the basis of surface chemical composition and surface roughness. The results demonstrated that corrosion resistance increased with increasing hydrophobicity of the SS surface.
关键词： corrosion resistance,femtosecond pulsed laser,stainless steel,surface micro-structuring,wettability
更新于2025-09-10 09:29:36
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High-rate deposition of silicon films in a magnetron discharge with liquid target
摘要： Silicon coatings have been deposited on substrates made of low-carbon and high-carbon steels and tungsten in a magnetron discharge with liquid target at substrate bias voltages ranging from +100 V to -600 V. The structure of obtained coatings was examined by a scanning electron microscopy. The strong influence of substrate bias voltage on the coating structure was observed. The corrosion resistance of coated steel samples was examined in concentrated sulphuric, hydrochloric and nitric acids and their solutions. The resistance of coated tungsten samples against high-temperature oxidation was examined by their exposure to O2 gas at a pressure of 0.2 Pa and a temperature of 1073 K. The coatings deposited under bias voltages of +100 V and -600 V had dense structures and showed the best protective properties among all deposited coatings.
关键词： high-temperature oxidation,silicon coatings,liquid target,corrosion resistance,magnetron discharge
更新于2025-09-10 09:29:36