Metallic biomaterials are increasingly being used in various medical applications due to their high strength,fracture resistance,good electrical conductivity,and biocompatibility.However,their practical applications h...Metallic biomaterials are increasingly being used in various medical applications due to their high strength,fracture resistance,good electrical conductivity,and biocompatibility.However,their practical applications have been largely limited due to poor surface performance.Laser microprocessing is an advanced method of enhancing the surface-related properties of biomaterials.This work demonstrates the capability of laser microprocessing for biomedical metallic materials including magnesium and titanium alloys,with potential applications in cell adhesion and liquid biopsy.We investigate laser-material interaction,microstructural evolution,and surface performance,and analyze cell behavior and the surface-enhanced Raman scattering(SERS)effect.Furthermore,we explore a theoretical study on the laser microprocessing of metallic alloys that shows interesting results with potential applications.The results show that cells exhibit good adhesion behavior at the surface of the laser-treated surface,with a preferential direction based on the textured structure.A significant SERS enhancement of 6×10^3 can be obtained at the laser-textured surface during Raman measurement.展开更多
Short and ultrashort pulse lasers offer excellent advantages in laser precision machining mainly because of their high pulse energy and low ablation threshold. The complex process of laser interaction with metals limi...Short and ultrashort pulse lasers offer excellent advantages in laser precision machining mainly because of their high pulse energy and low ablation threshold. The complex process of laser interaction with metals limits the indepth investigation into laser ablation. Numerical simulation is important in the study of fundamental mechanisms. This review explores the start-of-the-art methods for the theoretical simulation of the laser ablation of metals, including plasma formation and expansion. Laser-induced period surface structures are also studied.展开更多
As a simple, reproducible, and pollution-free technique with the potential of integration and automation, laser processing has attracted increasing attention. Laser processing, which includes laser polishing, laser cl...As a simple, reproducible, and pollution-free technique with the potential of integration and automation, laser processing has attracted increasing attention. Laser processing, which includes laser polishing, laser cleaning,and fabrication of laser-induced micro-/nano-structures, has been demonstrated to yield smooth, clean, functional surfaces and effective joining. Laser polishing is an advanced, highly efficient, and ecofriendly polishing technology. This study demonstrated the laser polishing of a selective laser-melted Inconel 718(IN718) superalloy and a titanium alloy sample. The surface roughnesses Raand Rzof the IN718 superalloy were respectively reduced from 8 and 33 μm to 0.2 and 0.8 μm, and the Raof the titanium alloy was reduced from 9.8 μm to 0.2 μm.Moreover, the wear resistance and corrosion resistance of the IN718 were apparently improved. As another surface-related processing method, laser cleaning was used to clean terminal blocks. Almost all the contaminants were removed, as verified by the absence of their chemical compositions and the decreased surface roughness. In addition, a superhydrophobic surface with a contact angle of over 160° and sliding angle of b8° on stainless steel was obtained by laser texturing treatment. These results demonstrate the high potential of laser processing in the scientific, technological, and industrial fields.展开更多
This paper proposes a scanner–stage synchronized approach emphasizing a novel control structure for the laser polishing of Inconel 718 components manufactured by selective laser melting in order to address increasing...This paper proposes a scanner–stage synchronized approach emphasizing a novel control structure for the laser polishing of Inconel 718 components manufactured by selective laser melting in order to address increasing demands for high surface quality in metal additive manufacturing.The proposed synchronized control system is composed of a motion decomposition module and an error synthesis module.The experimental results show that stitching errors can be avoided thanks to continuous motion during laser processing.Moreover,in comparison with the existing step-scan method,the processing efficiency of the proposed method is improved by 38.22%and the surface quality of the laser-polished area is significantly enhanced due to a more homogeneous distribution of the laser energy during the material phase change.The proposed synchronized system paves the way for high-speed,high-precision,and large-area laser material processing without stitching errors.展开更多
1.Introduction Titanium(Ti)alloys have been widely used in aerospace[1],biomedical industries[2],marine and offshore[3],due to their high yield strength,low density,good biocompatibility and outstanding corrosion resi...1.Introduction Titanium(Ti)alloys have been widely used in aerospace[1],biomedical industries[2],marine and offshore[3],due to their high yield strength,low density,good biocompatibility and outstanding corrosion resistance[4-6].Compared with traditional material processing methods,such as forging[7],stamping[8]and casting[9],additive manufacturing(AM)has attracted much attention to produce complex components close to their final prototypes with the formation of an ultrafine eutectoid microstructure caused by high cooling rates under multiple thermal cycles[2].展开更多
A nanopositioning system of both millimetric stroke and nanometric tracking accuracy is a key component for nanofabrication in many applications. In this paper, a novel bi-axial beam-flexure nano servo stage is propos...A nanopositioning system of both millimetric stroke and nanometric tracking accuracy is a key component for nanofabrication in many applications. In this paper, a novel bi-axial beam-flexure nano servo stage is proposed to support a direct writing system for femtosecond laser nanofabrication. The important features of the stage lie in: a mirror symmetric instead of rotational symmetric configuration is adopted to restrict cross axis coupling, and a novel Z-shaped guidance module is proposed to achieve relative large linear stiffness range, in addition a redundant constraints module is introduced to increase off-axis stiffness of the stage. Mechanical analysis and system identification are provided, with which a feedback control algorithm demonstrates the tracking capability for laser fabrication purposes. Based on the fabricated XY nano-stage, real time control and measurements are deployed, demonstrating the millimetric operating workspace and 77.8 nm(RMS) error of tracking a circular trajectory.展开更多
Laser additive manufacturing(LAM)is promising for fabricating multi-metallic component,but the mechanism of microstructural evolution at the interface of two metals is still needed to research further.In this study,a ...Laser additive manufacturing(LAM)is promising for fabricating multi-metallic component,but the mechanism of microstructural evolution at the interface of two metals is still needed to research further.In this study,a 316L stainless steel/Ti6Al4V alloy multi-metal was fabricated by LAM,and the mechanism of intermetallic phase transformation was deeply investigated.Results show that a strong reaction zone(SRZ)can be induced at the interface of the multi-metal.The phase constituents at the SRZ vary fromχ(Ti_(5)Fe_(17)Cr_(5))+Fe_(2)Ti+α′-Ti+β-Ti or FeTi to Fe_(2)Ti+χwhen the laser power is increased.When the scanning speed is further decreased,the thickness of the SRZ is significantly increased,andα′-Ti phase is also formed at this region besides Fe_(2)Ti andχphases.Moreover,the micro-hardness at the SRZ is increased,caused by the intermetallic phase transformation and elemental interdiffusion at the interface.展开更多
基金the National Key R&D Program of China(2018YFB1107400)the National Key Basic Research Program of China(2015CB059900)+1 种基金the National Natural Science Foundation of China(51705013)the Beijing Natural Science Foundation(3162019 and J170002).
文摘Metallic biomaterials are increasingly being used in various medical applications due to their high strength,fracture resistance,good electrical conductivity,and biocompatibility.However,their practical applications have been largely limited due to poor surface performance.Laser microprocessing is an advanced method of enhancing the surface-related properties of biomaterials.This work demonstrates the capability of laser microprocessing for biomedical metallic materials including magnesium and titanium alloys,with potential applications in cell adhesion and liquid biopsy.We investigate laser-material interaction,microstructural evolution,and surface performance,and analyze cell behavior and the surface-enhanced Raman scattering(SERS)effect.Furthermore,we explore a theoretical study on the laser microprocessing of metallic alloys that shows interesting results with potential applications.The results show that cells exhibit good adhesion behavior at the surface of the laser-treated surface,with a preferential direction based on the textured structure.A significant SERS enhancement of 6×10^3 can be obtained at the laser-textured surface during Raman measurement.
基金supported by the National Key Research and Development Program of China (2018YFB1107700)the National Natural Science Foundation of China (51705013, 51875313)。
文摘Short and ultrashort pulse lasers offer excellent advantages in laser precision machining mainly because of their high pulse energy and low ablation threshold. The complex process of laser interaction with metals limits the indepth investigation into laser ablation. Numerical simulation is important in the study of fundamental mechanisms. This review explores the start-of-the-art methods for the theoretical simulation of the laser ablation of metals, including plasma formation and expansion. Laser-induced period surface structures are also studied.
基金National Key Research and Development Program of China under Grant 2018YFB1107700, 2018YFB1107400, and 2016YFB1102503National Key Basic Research Program of China under Grant 2015CB059900+1 种基金National Natural Science Foundation of China under Grant 51705013Beijing Natural Science Foundation under Grant J170002
文摘As a simple, reproducible, and pollution-free technique with the potential of integration and automation, laser processing has attracted increasing attention. Laser processing, which includes laser polishing, laser cleaning,and fabrication of laser-induced micro-/nano-structures, has been demonstrated to yield smooth, clean, functional surfaces and effective joining. Laser polishing is an advanced, highly efficient, and ecofriendly polishing technology. This study demonstrated the laser polishing of a selective laser-melted Inconel 718(IN718) superalloy and a titanium alloy sample. The surface roughnesses Raand Rzof the IN718 superalloy were respectively reduced from 8 and 33 μm to 0.2 and 0.8 μm, and the Raof the titanium alloy was reduced from 9.8 μm to 0.2 μm.Moreover, the wear resistance and corrosion resistance of the IN718 were apparently improved. As another surface-related processing method, laser cleaning was used to clean terminal blocks. Almost all the contaminants were removed, as verified by the absence of their chemical compositions and the decreased surface roughness. In addition, a superhydrophobic surface with a contact angle of over 160° and sliding angle of b8° on stainless steel was obtained by laser texturing treatment. These results demonstrate the high potential of laser processing in the scientific, technological, and industrial fields.
基金The authors would like to acknowledge support from the National Natural Science Foundation of China(51875313 and 51705013)the Open Foundation of the State Key Laboratory of Tribology&Institute of Manufacturing Engineering(SKLT2019C09).
文摘This paper proposes a scanner–stage synchronized approach emphasizing a novel control structure for the laser polishing of Inconel 718 components manufactured by selective laser melting in order to address increasing demands for high surface quality in metal additive manufacturing.The proposed synchronized control system is composed of a motion decomposition module and an error synthesis module.The experimental results show that stitching errors can be avoided thanks to continuous motion during laser processing.Moreover,in comparison with the existing step-scan method,the processing efficiency of the proposed method is improved by 38.22%and the surface quality of the laser-polished area is significantly enhanced due to a more homogeneous distribution of the laser energy during the material phase change.The proposed synchronized system paves the way for high-speed,high-precision,and large-area laser material processing without stitching errors.
基金financially supported by the National Natural Science Foundation of China(No.51705013)the National Key Research and Development Program of China(Nos.2018YFB1106000,2018YFB1107400,2018YFB1107700,and 2016YFB1102503)。
文摘1.Introduction Titanium(Ti)alloys have been widely used in aerospace[1],biomedical industries[2],marine and offshore[3],due to their high yield strength,low density,good biocompatibility and outstanding corrosion resistance[4-6].Compared with traditional material processing methods,such as forging[7],stamping[8]and casting[9],additive manufacturing(AM)has attracted much attention to produce complex components close to their final prototypes with the formation of an ultrafine eutectoid microstructure caused by high cooling rates under multiple thermal cycles[2].
基金supported by Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(Grant No.20121028120)the National Natural Science Foundation of China(Grant No.61327003)+4 种基金the Open Foundation of the State Key Laboratory of Fluid Power andMechatronic Systems(Grant No.GZKF-201413)the Fundamental Research Funds of Shandong University(Grant No.2015JC034)the National Key Basic Research Program of China(Grant No.2015CB059900)Beijing Natural Science Foundation(Grant No.3162019)the Fundamental Research Funds of Beihang University(Grant No.74003401)
文摘A nanopositioning system of both millimetric stroke and nanometric tracking accuracy is a key component for nanofabrication in many applications. In this paper, a novel bi-axial beam-flexure nano servo stage is proposed to support a direct writing system for femtosecond laser nanofabrication. The important features of the stage lie in: a mirror symmetric instead of rotational symmetric configuration is adopted to restrict cross axis coupling, and a novel Z-shaped guidance module is proposed to achieve relative large linear stiffness range, in addition a redundant constraints module is introduced to increase off-axis stiffness of the stage. Mechanical analysis and system identification are provided, with which a feedback control algorithm demonstrates the tracking capability for laser fabrication purposes. Based on the fabricated XY nano-stage, real time control and measurements are deployed, demonstrating the millimetric operating workspace and 77.8 nm(RMS) error of tracking a circular trajectory.
基金supported by the Key Research and Develop Program of Anhui Province(No.202004b11020030)the China Postdoctoral Science Foundation(No.2020M680292)。
文摘Laser additive manufacturing(LAM)is promising for fabricating multi-metallic component,but the mechanism of microstructural evolution at the interface of two metals is still needed to research further.In this study,a 316L stainless steel/Ti6Al4V alloy multi-metal was fabricated by LAM,and the mechanism of intermetallic phase transformation was deeply investigated.Results show that a strong reaction zone(SRZ)can be induced at the interface of the multi-metal.The phase constituents at the SRZ vary fromχ(Ti_(5)Fe_(17)Cr_(5))+Fe_(2)Ti+α′-Ti+β-Ti or FeTi to Fe_(2)Ti+χwhen the laser power is increased.When the scanning speed is further decreased,the thickness of the SRZ is significantly increased,andα′-Ti phase is also formed at this region besides Fe_(2)Ti andχphases.Moreover,the micro-hardness at the SRZ is increased,caused by the intermetallic phase transformation and elemental interdiffusion at the interface.