With the continuous expansion of the application range of microelectromechanical systems,microdevice forming technology has achieved remarkable results.However,it is challenging to develop new microforming processes t...With the continuous expansion of the application range of microelectromechanical systems,microdevice forming technology has achieved remarkable results.However,it is challenging to develop new microforming processes that are low cost,environmentally friendly,and highly flexible;the high-energy shock wave in a cavitation bubble's collapse process is used as the loading force.Herein,a new process for the microbulging of the water-jet cavitation is proposed.A series of experiments involving the water-jet cavitation shock microbulging process for TA2 titanium foil is performed on an experimental system.The microforming feasibility of the water-jet cavitation is investigated by characterizing the shape of the formed part.Subsequently,the effects of the main parameters of the water-jet cavitation on the bulging profile,forming depth,surface roughness,and bulging thickness distribution of TA2 titanium foil are revealed.The results show that the plastic deformation increases nonlinearly with the incident pressure.When the incident pressure is 20 MPa,the maximum deformation exceeds 240 pm,and the thickness thinning ratio changes within 10%.The microbulging feasibility of water-jet cavitation is verified by this phenomenon.展开更多
To balance the manufacturing cost and customizability of automotive parts,a hybrid manufacturing process combining die-casting and selective laser melting(SLM)is proposed:starting with a conventional cast substrate,SL...To balance the manufacturing cost and customizability of automotive parts,a hybrid manufacturing process combining die-casting and selective laser melting(SLM)is proposed:starting with a conventional cast substrate,SLM is utilized to add additional geometric elements on top of it.For this hybrid process,the first priority is to prepare a substrate surface suitable for the subsequent SLM addition of the top-on elements.In this study,the original cast surface of AlSi7Mg was processed by sandblasting,wire electro-discharge machining,and laser remelting,respectively.Then,additional AlSi7Mg components were built on both the original cast and treated surfaces through SLM.After hybrid builds,these surfaces and resultant interfaces were examined by optical and scanning electron microscopes.Results indicate that the defect-free metallurgical joint between the cast and additively added parts can be formed on all surfaces except for the one processed by electro-discharge machining.The observed epitaxial grain growth crossing the interface implies a strong connection between the cast and the SLMed component.Despite these benefits,also mismatches in microstructure,residual stress level and element distribution between the two parts are identified.After a comprehensive assessment,laser remelting with no additional machining is recommended as the optimal surface treatment preceding SLM fabrication,because of its user-friendly operation,low cost,and high industrial feasibility.展开更多
基金Supported by Nati onal Natural Science Foundation of China(Grant Nos.51575245,51679112)Jiangsu Province Key Research and Development Program of China(Grant No.BE2016161),Jiangsu Province"Six Tale nts Peak"Project of China(Grant No.XNYQC-002).
文摘With the continuous expansion of the application range of microelectromechanical systems,microdevice forming technology has achieved remarkable results.However,it is challenging to develop new microforming processes that are low cost,environmentally friendly,and highly flexible;the high-energy shock wave in a cavitation bubble's collapse process is used as the loading force.Herein,a new process for the microbulging of the water-jet cavitation is proposed.A series of experiments involving the water-jet cavitation shock microbulging process for TA2 titanium foil is performed on an experimental system.The microforming feasibility of the water-jet cavitation is investigated by characterizing the shape of the formed part.Subsequently,the effects of the main parameters of the water-jet cavitation on the bulging profile,forming depth,surface roughness,and bulging thickness distribution of TA2 titanium foil are revealed.The results show that the plastic deformation increases nonlinearly with the incident pressure.When the incident pressure is 20 MPa,the maximum deformation exceeds 240 pm,and the thickness thinning ratio changes within 10%.The microbulging feasibility of water-jet cavitation is verified by this phenomenon.
基金financially supported by the Ford Motor Com-pany under Ford-KU Leuven University Research Alliance Frame-work KUL-0025 fortheproject‘Incremental Additive Manufacturing for Metal Applications’.Haiyang Fan also appreciates the financial support of the China Scholarship Council(CSC)(No.201606050132).
文摘To balance the manufacturing cost and customizability of automotive parts,a hybrid manufacturing process combining die-casting and selective laser melting(SLM)is proposed:starting with a conventional cast substrate,SLM is utilized to add additional geometric elements on top of it.For this hybrid process,the first priority is to prepare a substrate surface suitable for the subsequent SLM addition of the top-on elements.In this study,the original cast surface of AlSi7Mg was processed by sandblasting,wire electro-discharge machining,and laser remelting,respectively.Then,additional AlSi7Mg components were built on both the original cast and treated surfaces through SLM.After hybrid builds,these surfaces and resultant interfaces were examined by optical and scanning electron microscopes.Results indicate that the defect-free metallurgical joint between the cast and additively added parts can be formed on all surfaces except for the one processed by electro-discharge machining.The observed epitaxial grain growth crossing the interface implies a strong connection between the cast and the SLMed component.Despite these benefits,also mismatches in microstructure,residual stress level and element distribution between the two parts are identified.After a comprehensive assessment,laser remelting with no additional machining is recommended as the optimal surface treatment preceding SLM fabrication,because of its user-friendly operation,low cost,and high industrial feasibility.
基金supported by the National Natural Science Foundation of China(Grants 51421001,51504051 and 51701032)the Chongqing Science and Technology Commission in China(CSTC,2017jcyjAX0094 and cstc2015jcyjA90001