3篇
您的检索式：作者名="Bangfu Ding"
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| 1 | Developing a novel radial ultrasonic vibration-assisted grinding device and evaluating its performance in machining PTMCs显示文摘Particle-reinforcing titanium matrix composites(PTMCs)exhibit the sharp raising applications in modern industries owing to its extraordinary physical and mechanical properties.However,the poor grindability and unstable grinding processes due to the existence of TiC particles and TiB short fibres inside PTMCs,leading to the sudden grinding burn and low material removal rate.In this work,a novel radial ultrasonic vibration-assisted grinding(RUVAG)device with a special cross structure was developed to improve machining efficiency and avoid grinding burns.Meanwhile,the resonant modal and transient dynamic characteristics of radial ultrasonic vibration system were discussed.Comparative grinding performance experiments were then conducted under the conventional grinding(CG)and RUVAG using mono-layer cubic boron nitride abrasive wheels,in views of the grinding forces and force ratio,grinding temperature,and ground surface morphology.Results show that the ultrasonic vibration direction can be transformed effectively using the special cross structure of vibration converter,and better vibration homogeneity can be obtained.RUVAG has a smaller tangential grinding force by 5.0%–17.2%than that of CG,but a higher normal grinding force of 6.5%–14.9%,owing to the periodic impact of grinding wheels.In addition,RUVAG possesses a remarkable lower grinding temperature in range of 24.2%–51.8%and a higher material removal rate by 2.8 times compared with CG,resulting from the intermittent cutting behavior between the grinding wheel and workpiece.In this case,the sudden burn can be avoided during high-speed grinding processes.Moreover,the proportion of micro-fracture defects on machined surface is slightly increased once the ultrasonic vibration mode is employed because of the periodic impact on reinforced particles,whereas the pull-out defects of reinforced particles are reduced significantly. | Biao ZHAO Bangfu WU Yansong YUE Wenfeng DING Jiuhua XU Guoqiang GUO | 2023 | Chinese Journal of Aeronautics2023，36，7： | 0 |
| 2 | Enhancing thermoelectric performance of n-type AgBi_(3)S_(5)through synergistically optimizing the effective mass and carrier mobility显示文摘AgBi_(3)S_(5) is a new n-type thermoelectric material that is environmentally friendly and composed of elements of earth-abundant,non-toxic and high performance-cost ratio.This compound features an intrinsically low thermal conductivity derived from its complex monoclinic structure.However,the terrible electrical transport properties greatly limited the improvement of thermoelectric performance.Most previous studies considered that carrier concentration is the main reason for low electrical conductivity and focused on improving carrier concentration by aliovalent ion doping.In this work,we found that the critical parameter that restricts the electric transport performance of AgBi_(3)S_(5)was the extremely low carrier mobility instead of the carrier concentration.According to the Pisarenko relationships and density functional theory calculations,Nb doping can sharpen the conduction band of AgBi_(3)S_(5),which contributes to reducing the effective mass and improving the carrier mobility.With a further increase of the Nb doping content,the conduction band convergence can enlarge the effective mass and preserve the carrier mobility.Combined with the decrease in lattice thermal conductivity due to the intensive phone scattering,a maximum ZT value of~0.50 at 773 K was achieved in Ag_(0.97)Nb_(0.03)Bi_(3)S_(5),which was~109.6%higher than that of pure AgBi3S5.This work will stimulate the new exploration of high-performance thermoelectric materials in ternary metal sulfides. | Xin Qian Xiaoxue Zhang Haoran Guo Bangfu Ding Mingjing Chen Jiang-Long Wang Li-Dong Zhao Shu-Fang Wang | 2023 | Journal of Materiomics2023，9，5： | 0 |
| 3 | Grinding Characteristics of MoS_(2)-Coated Brazed CBN Grinding Wheels in Dry Grinding of Titanium Alloy显示文摘As an important green manufacturing process,dry grinding has problems such as high grinding temperature and insufficient cooling capacity.Aiming at the problems of sticking and burns in dry grinding of titanium alloys,grinding performance evaluation of molybdenum disulfide(MoS_(2))solid lubricant coated brazed cubic boron carbide(CBN)grinding wheel(MoS_(2)-coated CBN wheel)in dry grinding titanium alloys was carried out.The lubrication mechanism of MoS_(2)in the grinding process is analyzed,and the MoS_(2)-coated CBN wheel is prepared.The results show that the MoS_(2)solid lubricant can form a lubricating film on the ground surface and reduce the friction coefficient and grinding force.Within the experimental parameters,normal grinding force decreased by 42.5%,and tangential grinding force decreased by 28.1%.MoS_(2)lubricant can effectively improve the heat dissipation effect of titanium alloy grinding arc area.Compared with common CBN grinding wheel,MoS_(2)-coated CBN wheel has lower grinding temperature.When the grinding depth reaches 20μm,the grinding temperature decreased by 30.5%.The wear of CBN grains of grinding wheel were analyzed by mathematical statistical method.MoS_(2)lubricating coating can essentially decrease the wear of grains,reduce the adhesion of titanium alloy chip,prolong the service life of grinding wheel,and help to enhance the surface quality of workpiece.This research provides high-quality and efficient technical support for titanium alloy grinding. | Junshuai Zhao Biao Zhao Wenfeng Ding Bangfu Wu Ming Han Jiuhua Xu Guoliang Liu | 2023 | Chinese Journal of Mechanical Engineering2023，36，4： | 0 |
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