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26 results on '"Duan, Duanzhi"'

2. Ultra-Precision Machining Technology and Equipment for High-End Optical Elements

Author

Jiang Zhuangde, Li Changsheng, Sun Lin, Duan Duanzhi, Kang Chengwei, Chen Shanshan, Lin Qijing, and Yang Shuming

Subjects
optical element, precision manufacturing, ultra-precision machine tool, ultra-precision machining, optical fabrication, Engineering (General). Civil engineering (General), TA1-2040
Abstract

High-end optical elements determine the performance of high-end equipment. Researching the ultra-precision machining technology and equipment for high-end optical elements is crucial for strengthening China's manufacturing industry and satisfying the requirements of the high-end equipment industry. In this study, the ultra-precision machining methods and equipment for optical elements, high-performance basic components, and measurement methods and equipment used in ultra-precision optical machining are analyzed. Five development trends are summarized including extremalization of precision and size, integration of shape and performance, compounding of machining technologies, integration of machining and measurement, and intellectualization of equipment and processes. Through extensive survey and discussions, a technology roadmap for ultra-precision manufacturing of high-end optical elements by 2035 is proposed from the aspects of demand, goals, products, key technologies, application demonstrations, and guarantees. Furthermore, several development suggestions are proposed, including (1) optimizing the innovation system and establishing technical alliances by organizing superior resources, (2) increasing resource guarantees and laying out plans on basic and technical research,(3) strengthening talent cultivation to expand the scale of the multi-level talent team, and (4) building a solid foundation for industrial development and cultivating small-sized leading enterprises.

Published
2023
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20. Microstructure and performance of diamond composites fabricated by self-propagating high-temperature synthesis using high-frequency induction as a heat source

Author

Zhihui Lai, Duan Duanzhi, L.L. Han, H. T. Zhang, Bing Xiao, J. S. Liu, and W.H. Xu

Subjects
Materials science, 020502 materials, Metallurgy, Self-propagating high-temperature synthesis, Sintering, Diamond, 02 engineering and technology, engineering.material, 021001 nanoscience & nanotechnology, Microstructure, Grinding, Carbide, 0205 materials engineering, visual_art, visual_art.visual_art_medium, engineering, Cubic zirconia, Ceramic, Composite material, 0210 nano-technology
Abstract

A mixture of Al, Ti, Cu, Ni, and Sn was used as the matrix material to fabricate diamond composites and grinding heads through self-propagating high-temperature synthesis (SHS). High-frequency induction was used as a heat source for preheating to ignite SHS. The SHS was examined, and the microstructure of the reaction products was analyzed by scanning electron microscopy and X-ray diffraction. As a comparison, diamond composites and grinding heads were fabricated by hot pressed sintering (HPS) using Cu-based matrix. The grinding performance of heads was tested in the grinding of Zirconia ceramics. Results showed that ferromagnetic Ni was a key element without which SHS could not start. Increasing frequency prolonged preheating time and decreased combustion temperature. The increasement of Al + Ti content in the matrix aggravated the combustion temperature and thereby aggravated the porosity. The optimal grinding ratios of SHS grinding heads was reached when Al + Ti weight content was 30% and was only 4% lower than that of HPS ones. The grinding forces of SHS grinding heads was lower than that of HPS ones. Carbides Ti 3 AlC and Ti 3 AlC 2 formed on the diamond surface during SHS.

Published
2018

21. Investigation on the brazing mechanism and machining performance of diamond wire saw based on Cu-Sn-Ti alloy

Author

Bo Wang, Liu Sixing, Bing Xiao, Zhang Ziyu, and Duan Duanzhi

Subjects
0209 industrial biotechnology, Materials science, Carbon steel, Scanning electron microscope, Abrasive, Metallurgy, Alloy, Wire saw, Diamond, 02 engineering and technology, engineering.material, 021001 nanoscience & nanotechnology, 020901 industrial engineering & automation, Ultimate tensile strength, engineering, Brazing, Composite material, 0210 nano-technology
Abstract

Brazing connection between diamond particles and KSC82 carbon steel wire was established by the Cu-Sn-Ti alloy, and a diamond wire saw of 500 m in length and about 0.75 mm in diameter was fabricated. The brazing morphology of the diamond particles was observed using scanning electron microscopy (SEM), and the products and elemental distribution characteristics at the diamond brazed interface were analyzed by the energy disperse spectroscopy (EDS) and X-ray diffraction (XRD). The tensile mechanical properties of the brazed diamond wire saw was obtained through tensile tests, and the morphology of the fracture was observed using the SEM to analyze the tensile fracture mechanism. Further, the diamond wire saw was used for slice processing test of G663 granite, and the failure mode of the wire saw was analyzed. The results showed that there was Ti segregation at the diamond brazing interface, and that Ti 2 C new phase was detected at the interface, where brazing connection of diamond particles was achieved through by reactive wetting. The tensile and yield strengths of the brazing diamond wire saw were 1289.08 and 923.18 MPa respectively, its plasticity was twice that of original KSC82 steel wire, and the tensile failure mode of the wire saw was ductile fracture. The stable cutting efficiency of the brazing diamond wire saw cutting the G663 granite with cross-sectional dimensions of 480 mm × 260 mm could reach 15 mm/min. There were three abrasive wear modes for the diamond particles of the wire saw working layer, including normal wear, shear fracture and separation, of which separation accounted for 14.3%. The reason for the separation of diamond was attributed to the oxidation of Ti element in Cu-Sn-Ti alloy and the fatigue crack initiation and growth at the diamond brazing interface.

Published
2017

25. Effect of Cu[sbnd]Ce alloy addition on the microstructure and mechanical performance of brazed diamonds with Ni[sbnd]Cr alloy.

Author

Duan, Duanzhi, Sun, Lin, Lin, Qijing, Fang, Xudong, Li, Changsheng, and Jiang, Zhuangde

Subjects
*BRAZING, *DIAMONDS, *MICROSTRUCTURE, *ALLOYS, *SURFACE morphology, *METALLIC composites
Abstract

Abstract This study was aimed to reduce unwanted thermal damage to diamond grains during brazing. To achieve this goal, the diamonds were brazed using Ni Cr alloy with the addition of Cu Ce alloy (i.e. Ni Cr composite solder). Surface morphology and interfacial microstructure of the brazed samples using Ni Cr composite solder was characterized. The thermally induced residual stresses of brazed diamond grains were examined by Raman spectroscopy. The static pressure strength and impact toughness of the brazed diamond grains were examined. Constitutional phases of Ni Cr composite solder after brazing were detected. The results show that the thermal residual stresses values of the brazed diamond grains using Ni Cr composite solder, in which 2 wt% and 5 wt% Cu Ce alloy were used respectively, were decreased by 6.4% and 9.7% respectively, meanwhile, the static pressure strength values increased by 4.9% and 13.4% respectively as well as impact toughness values increased by 4.0% and 9.2% respectively, compared with that of the brazed diamond grains using Ni Cr alloy. Chromium carbides (Cr 3 C 2 and Cr 7 C 3) were obtained at the bonding interface between diamonds and composite solder. The constitutional phases containing Ce 2 Ni 7 , which could be beneficial to reduce the thermal damage, were formed in the solder alloy after brazing. Graphical abstract Unlabelled Image Highlights • The surface morphology of the brazed samples using Ni Cr composite solder was better. • Cr3C2 and Cr7C3 was obtained at the bonding interface between composite solder and diamonds. • The residual stresses values of the brazed diamonds were decreased using Ni Cr composite solder. • The increasing proportion of mechanical strength were higher than that of weight content of Cu Ce alloy. • The constitutional phases containing Ce2Ni7 were formed in the composite solder alloy. [ABSTRACT FROM AUTHOR]

Published
2019
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