| 1. |
- Bi, Lianjie, et al.
(författare)
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Effect of appropriate vibration frequency on microstructure and properties of laser cladding Co-based self-lubricating composite coatings
- 2024
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Ingår i: Welding in the World, Le Soudage Dans Le Monde. - 1878-6669 .- 0043-2288. ; 68:7, s. 1671-1683
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Tidskriftsartikel (refereegranskat)abstract
- CrS/NbC reinforced Co-based self-lubricating composite coatings were successfully prepared on the surface of Cr12MoV steel by high-frequency micro-vibration (HFMV) assisted laser cladding technology. The microstructure, phase composition, microhardness, and wear resistance of the composite coatings were studied by means of X-ray diffractometer (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), microhardness tester, and friction-wear tester. The results show that there were excellent metallurgical bonding and free of pores and cracks in the CrS/NbC Co-based self-lubricating composite coating with 10% WS2 prepared by laser cladding at 552 Hz vibration frequency. The appropriate vibration frequency could cause strong convection in the molten pool and refine the microstructure, which made NbC hard particulates and CrS lubricants to be evenly distributed in the composite coating. In particular, the refined CrS and NbC in the upper area of the coating were combined with each other to form a dense network microstructure. Moreover, the hardness of the coating prepared at the vibration frequency of 552 Hz was significantly improved due to its excellent microstructure compared with the without vibration and 985 Hz vibration frequencies and the maximum hardness reached 652.8 HV0.5. Its wear resistance was also significantly improved, and the friction coefficient of the coating was reduced to 0.451. Only abrasive wear and slight adhesive wear were observed on the coatings surface, and the tearing layer and wear loss of grinding defects were significantly reduced.
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| 2. |
- Bi, Lianjie, et al.
(författare)
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Influence of rare earth oxides on microstructure and mechanical properties of nickel-based superalloys fabricated by high energy beam processing: A review
- 2024
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Ingår i: Journal of Rare Earths. - 1002-0721. ; 42:9, s. 1629-1645
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Forskningsöversikt (refereegranskat)abstract
- In this paper, the effects of rare earth oxides on the microstructure and mechanical properties of nickel-based superalloys prepared by high-energy beam processing technology were critically studied. The focus is on the optimal amount of rare earth oxides that can produce ideal results. Special attention was paid to their main strengthening mechanisms, including solid solution strengthening mainly in the form of solid solution dissolved in the nickel-based alloy and improving the microstructure of the alloy by grain refinement or fine grain strengthening produced by homogenizing the distribution phase. Y2O3, La2O3 and CeO2 rare earth oxides can also improve the fluidity of the alloy molten pool and reduce the segregation of alloying elements. These advantages can significantly improve the mechanical properties of the alloy. Thereafter, this paper outlines the future research directions of rare earth oxides, aiming to expand their application potential.
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| 3. |
- Jiang, Haiying, et al.
(författare)
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A Highly Crystalline Wide-Band-Gap Conjugated Polymer toward High-Performance As-Cast Nonfullerene Polymer Solar Cells
- 2017
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Ingår i: ACS Applied Materials and Interfaces. - : AMER CHEMICAL SOC. - 1944-8244 .- 1944-8252. ; 9:41, s. 36061-36069
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Tidskriftsartikel (refereegranskat)abstract
- A new wide-band-gap conjugated polymer PBODT was successfully synthesized that showed high crystallinity and was utilized as, the active material in nonfullerene bulk-heterojunction, polymer solar cells (PSCs). The photovoltaic devices based on the as-cast blend films of PBODT with ITIC and IDIC acceptors showed notable power conversion efficiencies (PCEs) of 7.06% and 9:09%, with high open-circuit voltages of 1.00 and 0.93 V that correspond to low energy losses of 0.59 and 0.69 eV, respectively. In the case of PBODT:ITIC, lower exciton quenching efficiency and monomolecular recombination are found for devices with small driving force. On the other hand, the relatively higher driving force and suppressed monomolecular recombination for PBODT:IDIC devices are identified to be the reason for their higher short-circuit current density (J(sc)) and higher PCEs. In addition, when processed with the nonchlorinated solvent 1,2,4-trimethylbenzene, a good, PCE of 8.19% was still, achieved for the IDIC-based device. Our work shows that such wide-band-gap polymers have great potential for the environmentally friendly fabrication of highly efficient PSCs.
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