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Ding K.,Nanjing University of Aeronautics and Astronautics | Fu Y.,Nanjing University of Aeronautics and Astronautics | Su H.,Nanjing University of Aeronautics and Astronautics | He T.,Nanjing University of Aeronautics and Astronautics | And 2 more authors.
Key Engineering Materials | Year: 2014

In the present work, ultrasonic assisted grinding (UAG) and conventional grinding (CG, without ultrasonic) tests of Carbon fiber reinforced silicon carbide matrix (C/SiC) composites were conducted. In addition, analysis was done by comparing the machining quality, grinding force, and specific grinding energy between the two processes. The results showed that material removal mode of carbon fiber both in CG and UAG were brittle fracture, and fracture size had no obvious difference. Compared with CG, brittle fracture area of SiC increased during UAG. In comparison with CG, the normal grinding force and tangential grinding force for UAG were reduced maximally by 45%, 39% respectively of those for CG. Accordingly, specific grinding energy was also reduced by UAG. Therefore, UAG can improve the grinding performance of C/SiC composites significantly. © (2014) Trans Tech Publications, Switzerland. Source


Ding K.,Nanjing University of Aeronautics and Astronautics | Fu Y.,Nanjing University of Aeronautics and Astronautics | Su H.,Nanjing University of Aeronautics and Astronautics | Chen Y.,Nanjing University of Aeronautics and Astronautics | And 2 more authors.
Journal of Materials Processing Technology | Year: 2014

Carbon fiber reinforced silicon carbide matrix (C/SiC) composites have great potential in space applications because of their excellent properties such as low density, superior wear resistance and high temperature resistance. However, the use of C/SiC has been hindered seriously because of its poor machining characteristics. With an objective to improve the machining process of C/SiC composites, rotary ultrasonic machining (RUM) and conventional drilling (CD) tests with a diamond core drill were conducted. The effects of ultrasonic vibration on mechanical load and machining quality were studied by comparing the drilling force, torque, quality of holes exit and surface roughness of drilled holes between the two processes. The results showed that the drilling force and torque for RUM were reduced by 23% and 47.6%, respectively of those for CD. In addition, the reduction in drilling force and torque decreased gradually with increasing spindle speed, while they changed slightly with increasing feed rate. Under identical conditions, RUM gave better holes exit than CD. Moreover, because of the lower lamellar brittle fracture and pit originating from carbon fibers fracture, the roughness of surface of drilled holes obtained with RUM was lower than CD and the maximum reduction was 23%. © 2014 Elsevier B.V. Source


Ding K.,Nanjing University of Aeronautics and Astronautics | Fu Y.-C.,Nanjing University of Aeronautics and Astronautics | Su H.-H.,Nanjing University of Aeronautics and Astronautics | He T.,Nanjing University of Aeronautics and Astronautics | And 2 more authors.
Jingangshi yu Moliao Moju Gongcheng/Diamond and Abrasives Engineering | Year: 2014

Surface grinding tests were conducted on two-dimensional orthogonal fabricated C/SiC materials with resin bond diamond wheel. The ground morphology and surface roughness in carbon area were analyzed. The damage of the ground surface and subsurface was studied. The results showed that the main damage of carbon fiber was terraced fracture. In addition, for the area which paralleled to the feedrate, the fracture size and surface roughness were slightly affected by grinding parameters, while for carbon fiber area which was vertical to the feedrate, fracture size and surface roughness changed slightly with increasing feedrate, but increased significantly with increasing grinding depth. For SiC area, the main subsurface damages was brittle fracture and micro crack, and the damage size was affected slightly by grinding parameters. Source


Wei H.,Harbin Institute of Technology | Li W.,Harbin Institute of Technology | Li W.,Aerospace Research Institute of Materials And Processing Technology | He P.,Harbin Institute of Technology | And 3 more authors.
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2015

Ti3Al and Ti2AlNb alloy were connected by diffusion bonding with Ti foil as interlayer. Through a number of analysis methods such as SEM, EDS and XRD, it was discovered that the typical interface structure of Ti3Al/Ti/Ti2AlNb joint was Ti3Al/α-phase + β-phase/B2-rich phase/Ti2AlNb. The effect of process parameters, including thickness of interface layer, bonding temperature and holding time, on the interface morphology and property of the joint was investigated. The results show that when the thickness of Ti foil was 10 μm, bonding temperature was 900 ℃ and holding time was 120 min, the resultant Ti3Al/Ti/Ti2AlNb joint had the optimized microstructure and properties. Increasing the foil thickness caused uneven diffusion of Ti, Al and Nb. The direct bonding temperature of Ti3Al/Ti2AlNb was 1 000 ℃, the addition of Ti foil interlayer could reduce the bonding temperature to 900 ℃. So the damage of high temperature thermal cycling to Ti3Al alloy was decreased. The tensile strength of the joint increased from 795 MPa to 906 MPa. The holding time from 90 min to 120 min could ensure sufficient diffusion and reliable connection. ©, 2015, Harbin Research Institute of Welding. All right reserved. Source


Han W.B.,Harbin Institute of Technology | Zhang J.H.,Mudanjiang Jingangzuan Boron Carbide Co..Ltd | Yang H.Q.,Beijing Xinghang Mechanical and Electrical Equipment Co. | Ding G.Z.,Beijing Xinghang Mechanical and Electrical Equipment Co.
Advanced Materials Research | Year: 2013

ZrB2-SiC ceramic composites with the addition of carbon black were fabricated by hot pressed sintering at 1900 °C for 60 min at a uniaxial pressure of 30 MPa in an argon atmosphere. The mechanical properties of ZrB2-SiC ceramic composites were improved, adapting to the use requirements of ceramic parts. The precision electromachining technology of complicated structure components was investigated. The processing surface roughness was evaluated. © (2013) Trans Tech Publications, Switzerland. Source

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