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Author

Yi Zhang

Bio: Yi Zhang is an academic researcher. The author has contributed to research in topics: Materials science & Microstructure. The author has an hindex of 4, co-authored 6 publications receiving 28 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the effect of heat treatment at 550°C combined with a subsequent slow cooling rate on microstructure and mechanical properties of maraging 18Ni-300 steel obtained by the powder bed based selective laser melting (SLM) process was investigated.
Abstract: The purpose of this paper is to maraging 18Ni-300 steel fabricate by powder bed based selective laser melting (SLM) process. Microstructure and mechanical properties of the maraging steel part before and after heat treatment at a slow cooling rate were investigated.,The microstructure of the printed part was observed by optical microscopy and scanning electron microscopy. The phases were determined by X-ray diffraction. The surface roughness of the part was recorded by a profilometer. The tensile properties and microhardness of the parts before and after heat treatment were characterized by an electronic universal tensile testing machine and a Vickers hardness tester, respectively.,Maraging 18Ni-300 steel part comprised of the martensitic phase and a small fraction of austenite phase. After heat treatment, the volume fraction of austenite slightly increased. The surface roughness of the part was about 96 µm. The printed part was dense, but irregular pores were present. The yield strength, ultimate tensile strength (UTS), elongation and Young’s modulus of as-fabricated parts were 554.7 MPa, 1173.1 MPa, 10.9% and 128.9 GPa, respectively. The yield strength, UTS, elongation and Young’s modulus of as-treated parts were 2065 MPa, 2225 MPa, 4.2% and 142.5 GPa, respectively. The microhardness values of surface and cross-section of the as-fabricated part were 407.1 HV and 443.0 HV, respectively. After short-time heat treatment, the microhardness values of the surface and cross-section of the part were 542.7 HV and 567.3 HV, respectively. After long-time heat treatment, the microhardness values of the surface and cross-section of the part were 524.4 HV and 454.8 HV, respectively. The microhardness and tensile strength increased significantly with decreasing elongation due to the changes in phases and microstructure of the parts after heat treatment.,This work studied the effect of heat treatment at 550°C combined with a subsequent slow cooling rate on microstructure and mechanical properties of maraging 18Ni-300 steel obtained by the powder bed based SLM process.

15 citations

Journal ArticleDOI
TL;DR: Iridium coating was fabricated by a double glow plasma discharge process on titanium alloy substrates and the electrochemical behaviours of the coating and the substrate were studied and compa....
Abstract: Iridium coating was fabricated by a double glow plasma discharge process on titanium alloy substrates. The electrochemical behaviours of the coating and the substrate were studied and compa...

13 citations

Journal ArticleDOI
TL;DR: In this article, a batch of fire detectors used in the aircraft has been corroded under containing sulfur atmosphere, and the chemical composition and phases of corrosion products were determined by energy dispersive spectrometer and X-ray diffraction, respectively.

11 citations

Journal ArticleDOI
TL;DR: In this article, the influence of current density and bath temperature on phases, crystal structure, microstructure, and deposition rate of rhodium films was studied by X-ray diffraction and scanning electron microscopy, respectively.
Abstract: Rhodium films were electrodeposited galvanostatically on copper–zinc alloy substrates from sulfate–phosphate aqueous solutions, in order to obtain a smooth, dense, and thick Rh film for electrical contacts. The influence of current density and bath temperature on phases, crystal structure, microstructure, and deposition rate of the film was studied. The phases and crystal structure, as well as microstructure of the film were determined by X-ray diffraction and scanning electron microscopy, respectively. The results showed that the current density and bath temperature had a significant influence on electrodeposition of rhodium film. The particles or aggregates on the surface evolved from fine to coarse and large with the increase of current density and bath temperature. By adjusting the deposition conditions, the optimized current density and bath temperature were 6.4–12.7 mA cm−2 and 50 °C, respectively. The film was composed of polycrystalline phase with monometallic form. The film was uniform and dense at low current density. The thickness of the film was up to 1.38–2.1 μm. At the optimal temperature of 50 °C, the surface of the film was smooth and fine. At the same time, the electrodeposition mechanism of the film was discussed. Rhodium films were electrodeposited from sulfate–phosphate aqueous solutions. The influence of current density and bath temperature on electrodeposition of the film was studied, and at the same time, the electrodeposition mechanism of the film was addressed.

9 citations

Journal ArticleDOI
TL;DR: In this paper, an as-deposited iridium-nickel (Ir-Ni) thin film was used as an electrocatalyst for hydrogen evolution reaction (HER) in an electrolyte containing 13.5 m sodium hexabromidate(III) and 40.5m Ni sulphate hexahydrate.
Abstract: Iridium–nickel (Ir–Ni) film is of great interest for catalytic and corrosive environment applications. Ir–Ni thin films as an electrocatalyst for hydrogen evolution reaction (HER) were galvanostatically electrodeposited on copper (Cu) foam from an electrolyte containing 13.5 mM sodium hexabromoiridate(III) and 40.5 mM Ni sulphate hexahydrate, simultaneously compared with electrodeposited Ir and Ni thin films. The top surface morphology of the film was characterized by scanning electron microscopy. The chemical composition of the film was determined by energy-dispersive spectroscopy and X-ray photoelectron spectroscopy. The electrocatalytic performance was performed by linear sweep voltammogram and cyclic voltammetry. The results showed that Ir–Ni thin film adhered to Cu foam and the surface appeared much rougher than the surface of Ni film. The chemical composition of Ir in the deposit was 80 ± 1.2 at.%. The film was composed of nanograins. The top surface of as-deposited film was mainly composed of metallic state. However, the top surface of the film consisted of oxides states, such as Ni oxides or Ni(OH)2, and Ir oxides after electrochemical measurements. As-deposited Ir–Ni thin film with large real active area exhibited high efficient electrocatalytic activity for HER, and achieved a current density of 10 mA cm2 at an overpotential of 60 mV and a Tafel slope of 40 mV dec−1, which is superior to pure Ir and Ni thin films. The remarkable increase in electrocatalytic activity for Ir–Ni film was ascribed to both increased surface area of active centers due to relatively rough and electrocatalytic synergism of Ir and Ni for the HER. Ir–Ni thin film electrodeposited on a foam copper electrode was used as an electrocatalyst for HER. The surface of as-deposited film was composed of metallic state. As-deposited Ir–Ni thin film with large real active area exhibited high efficient electrocatalytic activity for HER, and achieved a current density of 10 mA cm2 at an overpotential of 60 mV and a Tafel slope of 40 mV dec−1, which is superior to pure iridium and Ni thin films. As-deposited film possessed a good stability by accelerated degradation studies.

8 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, the authors reviewed the mechanisms of various Ir-based catalysts in hydrogen evolution reaction and oxygen evolution reaction (OER), including metal, alloys, and oxides.

152 citations

Journal ArticleDOI
TL;DR: In this article , a polyethersulfone (PES) membrane matrix was firstly coated by magnetic Ni via an in-situ reduction reaction, and then incorporated into a PES-Ni@UiO-66 membrane.

93 citations

Journal ArticleDOI
TL;DR: In this paper, the double glow plasma surface alloying (DGPSA) technology has been used for improving the surface properties of materials in various environments, and the layer prepared by DGPSA technology is developing toward alloying, functionalization and nanometer.
Abstract: Higher performance is steadily required in the field of material surface engineering, especially in terms of surface degradation of mechanical parts and repair and renewal of surfaces. By preparing a more reasonable surface design and improving the surface composition and structure of the material, the surface modification layer can provide an important potential solution to the surface degradation problem. The coatings obtained by double glow plasma surface alloying (DGPSA) technology are a compelling method in current and future applications because of a unique combination of characteristics including pollution-free, the gradient distribution of the alloying elements and the strong metallurgical bonding between the alloying layer and the matrix. In recent years, with the increasing requirements for the surface properties of materials in various environments, the layer prepared by DGPSA technology is developing toward alloying, functionalization and nanometer. This review begins with a brief introduction of double glow plasma surface alloying. The recent developments of the double glow plasma surface alloying technology for improving various surface performance are systematically reviewed in the sight of applied material, background, duplex treatment and duplex coating preparation.

44 citations

Journal ArticleDOI
TL;DR: In this paper, iridium-cobalt (Ir-Co) thin films were galvanostatically electrodeposited on a copper (Cu) foam electrode as an electrocatalyst for water splitting in 1.0 M KOH alkaline medium.

34 citations

Journal ArticleDOI
TL;DR: In this paper, the multiaxial fatigue behavior of steel samples produced by selective laser melting was studied and the cyclic plasticity at the notch-controlled process zone was accounted for by combining the equivalent strain energy density concept and the theory of critical distances within a linear-elastic framework.

34 citations