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Effect of quenching cooling rate on residual stress and microstructure evolution of 6061 aluminum alloy
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作者 HUANG Ke YI You-ping +4 位作者 HUANG Shi-quan HE Hai-lin LIU Jie HUA Hong-en TANG Yun-jian 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2167-2180,共14页
In this study,the cooling rate was manipulated by quenching with water of different temperatures(30,60 and 100℃).Surface and internal residual stresses in the quenched 6061 aluminum alloy samples were measured using ... In this study,the cooling rate was manipulated by quenching with water of different temperatures(30,60 and 100℃).Surface and internal residual stresses in the quenched 6061 aluminum alloy samples were measured using hole-drilling and crack compliance methods,respectively.Then,the processability of the quenched samples was evaluated at cryogenic temperatures.The mechanical properties of the as-aged samples were assessed,and microstructure evolution was analyzed.The surface residual stresses of samples W30℃,W60℃and W100℃is−178.7,−161.7 and−117.2 MPa,respectively along x-direction,respectively;and−191.2,−172.1 and−126.2 MPa,respectively along y-direction.The sample quenched in boiling water displaying the lowest residual stress(~34%and~60%reduction in the surface and core).The generation and distribution of quenching residual stress could be attributed to the lattice distortion gradient.Desirable plasticity was also exhibited in the samples with relatively low quenching cooling rates at cryogenic temperatures.The strengthes of the as-aged samples are 291.2 to 270.1 MPa as the quenching water temperature increase from 30℃to 100℃.Fine and homogeneous β"phases were observed in the as-aged sample quenched with boiling water due to the clusters and Guinier-Preston zones(GP zones)premature precipitated during quenching process. 展开更多
关键词 6061 aluminum alloy residual stress cooling rate cryogenic cooling mechanical properties microstructure evolution
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Effect of cryogenic cooling in milling process of AISI 304 stainless steel 被引量:1
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作者 Muammer NALBANT Yakup YILDIZ 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第1期72-79,共8页
The effects of cryogenic cooling on cutting forces in the milling process of AISI 304 stainless steel were investigated experimentally.Cryogenic cooling was achieved by spraying liquid nitrogen to tool,chips and mater... The effects of cryogenic cooling on cutting forces in the milling process of AISI 304 stainless steel were investigated experimentally.Cryogenic cooling was achieved by spraying liquid nitrogen to tool,chips and material interfaces using a pipe with an internal diameter of 1 mm;the flow rate of liquid nitrogen was 5.2 L/min;two cutting directions(climbing and conventional milling),two machining conditions(dry and cryogenic cooling) and four cutting speeds(80,120,160 and 200 m/min) were used in the milling process.Cryogenic cooling and cutting speed are found to be effective on cutting forces.Cutting forces and torque in cryogenic milling are higher than those in dry milling.Cutting force is increased as the cutting speed is increased.Tool fritter around insert nose radius is the main problem of climb milling method in cryogenic cooling at low cutting speeds. 展开更多
关键词 cryogenic cooling AISI 304 cutting force tool frittering
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Cooling and lubrication techniques in grinding:A state-of-the-art review,applications,and sustainability assessment 被引量:2
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作者 Ahmed Mohamed Mahmoud IBRAHIM Wei LI +6 位作者 Abdel-Hamid ISMAIL MOURAD Mohamed A.E.OMER Fadl A.ESSA Ahmed Mustafa ABD EL-NABY Mohammad S.Al SOUFI Muhammad F.EZZAT Ammar ElSHEIKH 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2023年第7期76-113,共38页
Grinding technology is an essential manufacturing operation,in particular,when a component with a superfinishing and an ultra-resolution is yearned.Meeting the required strict quality checklist with maintaining a high... Grinding technology is an essential manufacturing operation,in particular,when a component with a superfinishing and an ultra-resolution is yearned.Meeting the required strict quality checklist with maintaining a high level of productivity and sustainability is a substantive issue.The recent paper outlines the lubrication and cooling technologies and mediums that are used for grinding.Furthermore,it provides a basis for a critical assessment of the different lubrication/cooling techniques in terms of machining outputs,environmental impact,hygiene effect,etc.Meanwhile,the paper put light on the sustainability of different cooling/lubrication strategies.The sustainability of machining aims to get the product with the best accuracy and surface quality,minimum energy consumption,low environmental impact,reasonable economy,and minimum effect on worker’s health.The paper revealed that despite some cooling/lubrication mediums like mineral oils and semisynthetic,afford sufficient lubrication or cooling,they have a significant negative impact on the environment and public health.On the other hand,emulsions can overcome environmental problems but the economy and the energy consumption during grinding are still a matter of concern.Biodegradable and vegetable oils are considered eco-friendly oils,but they suffer from a lack of thermal stability which affects their ability of efficiently cooling.Using the cooling medium with the lowest amount can achieve the goal of the economy but it may be reflected negatively on the machinability.Furthermore,cryogenic lubrication doesn’t provide sufficient lubrication to reduce friction and hence energy consumption.The research described in the paper is such a comprehensive compilation of knowledge regarding the machinability and machining performance under different cooling and lubrication systems that it will aid the next generation of scientists in identifying current advancements as well as potential future directions of research on ecological aspects of machining for sustainability. 展开更多
关键词 cryogenic cooling Dry lubrication Minimum quantity lubrication Precision grinding Solid lubrication Sustainable machining Vegetable oils
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Cryogenic Photodetachment Spectroscopy and High-Resolution Resonant Photoelectron Imaging of Cold para-Ethylphenolate Anions
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作者 Dao-Fu Yuan Yue-Rou Zhang +2 位作者 Chen-Hui Qian Guo-Zhu Zhu Lai-Sheng Wang 《Precision Chemistry》 2023年第3期161-174,共14页
Valence-bound molecular anions with polar neutral cores(μ>2.5 D)can support highly diffuse dipole-bound states(DBSs)as electronically excited states just below the detachment threshold.Such weakly bound nonvalence... Valence-bound molecular anions with polar neutral cores(μ>2.5 D)can support highly diffuse dipole-bound states(DBSs)as electronically excited states just below the detachment threshold.Such weakly bound nonvalence excited states have little influence on the structure of the neutral core,and they usually have the same vibrational frequencies.DBSs can be systematically searched using photodetachment spectroscopy(PDS),which can yield the binding energies of the DBSs,the electron detachment threshold of the anion,and above-threshold vibrational levels of the DBSs(Feshbach resonances).We have shown that the combination of PDS and resonant photoelectron spectroscopy(rPES)at the Feshbach resonances is a powerful approach to obtain rich vibrational information for complex molecular radicals.A prerequisite for this technique is to produce vibrationally cold anions,made possible by a cryogenically controlled Paul trap.In this article,we report a PDS and rPES study of cold para-ethylphenolate anions(p-EP^(-)).The electron affinity of the p-EP radical is measured to be 17425±3 cm^(-1)(2.1604±0.0004 eV),and a DBS is found at 145 cm^(-1) below the detachment threshold of p-EP^(-).Thirty-four vibrational levels are observed for the DBS,including two bound levels and 32 Feshbach resonances.Frequencies for 17 vibrational modes of the p-EP radical are measured from the combination of PDS and rPES,including six symmetry-forbidden modes with A″symmetry.The current study confirms again the power of combining cryogenic ion cooling with PDS and highresolution rPES to obtain spectroscopic information on complex molecular radicals. 展开更多
关键词 dipole-bound state photoelectron imaging cryogenic ion cooling resonant photoelectron spectroscopy ethylphenoxy radical vibrational frequencies electrospray ionization
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Effect of cooling strategies on performance and mechanism of helical milling of CFRP/Ti-6Al-4V stacks 被引量:6
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作者 Jiaying GE Guang CHEN +4 位作者 Yongxiang SU Yunhe ZOU Chengzu REN Xuda QIN Guofeng WANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2022年第2期388-403,共16页
Hole-making for Carbon Fiber Reinforced Plastics(CFRP)/Ti-6Al-4V stacks is crucial for the assembling strength of aircraft structure parts.This work carried out experimental work for helical milling(HM)of the stacks w... Hole-making for Carbon Fiber Reinforced Plastics(CFRP)/Ti-6Al-4V stacks is crucial for the assembling strength of aircraft structure parts.This work carried out experimental work for helical milling(HM)of the stacks with sustainable cooling/lubrication(dry,MQL and cryogenic)conditions.Cutting forces and temperatures at the CFRP layer,Ti-6Al-4V layer and the interface of stacks were obtained by a developed measuring system.The temperatures in CFRP machining at cryogenic condition varied from-167℃to-94℃,which were much lower than those at dry and MQL conditions.The maximum temperature near the interface of stacks for the ninth hole was higher than 240℃due to heat conduction from Ti-6Al-4V layer.The hole quality,hole diameter and tool wear mechanism at different cooling/lubrication conditions were presented and discussed.MQL condition generated mainly extrusion fracture for the fibers,due to the reduced friction effect compared with dry condition.MQL was helpful to reduce the feed mark at the hole surface of Ti-6Al-4V alloy.The flank wear of cutting edge at MQL condition was better than those at dry and cryogenic conditions.Cryogenic cooling contributed to better CFRP surface with smaller delamination and hole entrance damage due to the increased resin strength and fiber brittleness.The damage near the entrance of CFRP were analyzed by the contact state of cutting edges and fibers.Additionally,hole diameters near the exit of CFPR layer were larger than other test positions.This work provided feasible processes for improving hole quality and tool life in hole-making of CFRP/Ti-6Al-4V stacks. 展开更多
关键词 CFRP/Ti-6Al-4V stacks cryogenic cooling Cutting temperature Helical milling MQL
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Experimental investigation of tool wear and chip formation in cryogenic machining of titanium alloys 被引量:5
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作者 D. Biermann H. Abrahams M. Metzger 《Advances in Manufacturing》 SCIE CAS CSCD 2015年第4期292-299,共8页
Titanium alloys are one of the most important design materials for the aircraft industry. The high strength-to-density-ratio and the compatibility with carbon fibre reinforced plastic are the reasons for a raising app... Titanium alloys are one of the most important design materials for the aircraft industry. The high strength-to-density-ratio and the compatibility with carbon fibre reinforced plastic are the reasons for a raising application in this field. The outstanding properties lead to challenging machining processes. High strength and low heat conductivity affect high mechanical and thermal loads for the cutting edge. Thus, the machining process is characterized by a rapid development of tool wear even at low cutting parameter. To reach a sufficient productivity it is necessary to dissipate the resulting heat from the cutting edge by a coolant. Therefore the cryogenic machining of two different titanium alloys is investigated in this work. The results point out the different behavior of the machining processes under cryogenic conditions because of the reduced thermal load for the cutting tool. According to this investigation, the cryogenic cooling with COa enables an increase of the tool life in comparison to emulsion based cooling principles when machining the α+β-titanium alloy Ti-6Al-4V. The machining process of the high strength titanium alloy Ti-6Al-2Sn-4Zr-6Mo requires an additional lubrication realized by a minimum quantity lubrication (MQL) with oil. This combined cool- ing leads to a smoother chip underside and to slender shear bands between the different chip segments. 展开更多
关键词 Titanium alloys . cryogenic cooling Machining . Tool wear - Chip formation
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Pushing the boundaries of diode-pumped solid-state lasers for high-energy applications 被引量:4
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作者 Saumyabrata Banerjee Paul Mason +10 位作者 Jonathan Phillips Jodie Smith Thomas Butcher Jacob Spear Mariastefania De Vido Gary Quinn Danielle Clarke Klaus Ertel Cristina Hernez-Gomez Chris Edwards John Collier 《High Power Laser Science and Engineering》 SCIE CAS CSCD 2020年第2期77-79,共3页
We report on the successful demonstration of a 150 J nanosecond pulsed cryogenic gas cooled,diode-pumped multi-slab Yb:YAG laser operating at 1 Hz.To the best of our knowledge,this is the highest energy ever recorded ... We report on the successful demonstration of a 150 J nanosecond pulsed cryogenic gas cooled,diode-pumped multi-slab Yb:YAG laser operating at 1 Hz.To the best of our knowledge,this is the highest energy ever recorded for a diodepumped laser system. 展开更多
关键词 cryogenic gas cooling diode-pumped solid-state laser multi-slab amplifier YB:YAG
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