Ion beam irradiation was adopted for surface treatment of the micro punch manufactured by precision machining.Ar plasma was used for the ion irradiation process,which was generated by the electron cyclotron resonance(...Ion beam irradiation was adopted for surface treatment of the micro punch manufactured by precision machining.Ar plasma was used for the ion irradiation process,which was generated by the electron cyclotron resonance(ECR)equipment.The surface finish processes of micro punch were carried out at irradiation angles of 45°and 10°,respectively.The surface roughness and topography were measured to estimate the quality of surface finish.The results show that the ion irradiation is very effective to reduce the surface roughness,which can be improved more significantly at irradiation angle of 10°than at 45°.The technology of surface finish with ion beam irradiation is suitable for the surface treatment of micro die.展开更多
Prediction of surface finish in turning process is a difficult but important task. Artificial Neural Networks (ANN) can reliably pred ict the surface finish but require a lot of training data. To overcome this prob le...Prediction of surface finish in turning process is a difficult but important task. Artificial Neural Networks (ANN) can reliably pred ict the surface finish but require a lot of training data. To overcome this prob lem, an expert system approach is proposed, wherein it will be possible to predi ct the surface finish from limited experiments. The expert system contains a kno wledge base prepared from machining data handbooks and number of experiments con ducted by turning steel rods, over a wide range of cutting parameters. With this knowledge base, the expert system predicts surface finish for different tool-w ork-piece combinations, by carrying out few experiments for each case. The prop osed expert system model is validated by carrying out a number of experiments.展开更多
Metal framework composites have higher mechanical properties in examination to metals over an extensive variety of working conditions. This makes them an alluring alternative in swapping metals for different building ...Metal framework composites have higher mechanical properties in examination to metals over an extensive variety of working conditions. This makes them an alluring alternative in swapping metals for different building applications. The present review is a study on the influence of composite titanium on the cutting parameters, mechanical behavior, reinforcements, structure and nanostructure. This review will provide an understanding into selecting the optimum machining parameters for machining titanium composites. It’s also an attempt to give brief explanation by suitably machining the titanium composite which can be made reasonable.展开更多
This work focuses on the structure and magnetic properties of Fe-50wt% Ni permalloy manufactured from the pre-alloyed powder by selective laser melting (SLM). The selective laser melted (SLMed) alloys were characteriz...This work focuses on the structure and magnetic properties of Fe-50wt% Ni permalloy manufactured from the pre-alloyed powder by selective laser melting (SLM). The selective laser melted (SLMed) alloys were characterized by a 3D profilometer,optical microscope, scanning electron microscope, X-ray diffraction, etc. The effects of the volume energy density of laser(LVED) on structure, and magnetic properties with coercivity ( H), remanence ( B), and power losses ( P), were evaluated and discussed systematically. The results show that the relative porosity rate and the surface roughness of the SLMed specimens decreased with the increase in LVED. Only the γ-(FeNi) phase was detected in the X-ray diffraction patterns of the SLMed permalloys fabricated from the different LVEDs. Statistical analysis of optical microscopy images indicated that the grain coarsened at higher LVED. Furthermore, the microstructure of the SLMed parts was a typical columnar structure with an oriented growth of building direction. The highest microhardness reached 198 HV. Besides, the magnetic properties including B, H, and Pof SLMed samples decreased when the LVED ranged from 33.3 to 60.0 J/mm ~3 firstly and then increased while LVED further up to 93.3 J/mm, which is related to the decrease in porosity and the increase in grain size, while the higher residual stress and microcracks presented in the samples manufactured using very high LVED. The observed evolution of magnetic properties and LVED provides a good compromise in terms of reduced porosity and crack formation for the fabrication of SLMed Fe-50 wt% Ni permalloy. The theoretical mechanism in this study can offer guidance to further investigate SLMed soft magnetic alloys.展开更多
The formation of a heterogeneous oxidized layer,also called scale,on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys.Partial or total removal of the scale represents a...The formation of a heterogeneous oxidized layer,also called scale,on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys.Partial or total removal of the scale represents a mandatory integrated step for the industrial fabrication processes of medical devices.For biodegradable metals,acid pickling has already been reported as a preliminary surface preparation given further processes,such as electropolishing.Unfortunately,biodegradable medical prototypes presented discrepancies concerning acid pickling studies based on samples with less complex geometry(e.g.,non-uniform scale removal and rougher surface).Indeed,this translational knowledge lacks a detailed investigation on this process,deep characterization of treated surfaces properties,as well as a comprehensive discussion of the involved mechanisms.In this study,the effects of different acidic media(HCl,HNO_(3),H_(3)PO_(4),CH_(3)COOH,H_(2)SO_(4) and HF),maintained at different temperatures(21 and 60℃)for various exposition time(15-240 s),on the chemical composition and surface properties of a Fe-13Mn-1.2C biodegradable alloy were investigated.Changes in mass loss,morphology and wettability evidenced the combined effect of temperature and time for all conditions.Pickling in HCl and HF solutions favor mass loss(0.03-0.1 g/cm^(2))and effectively remove the initial scale.展开更多
Uniform poly-α-methylstyrene(PAMS)hollow core microcapsules(HCMs)are widely used as templates to fabricate glow discharge polymer(GDP)fuel capsules,which are fundamental devices for inertial confinement fusion(ICF)en...Uniform poly-α-methylstyrene(PAMS)hollow core microcapsules(HCMs)are widely used as templates to fabricate glow discharge polymer(GDP)fuel capsules,which are fundamental devices for inertial confinement fusion(ICF)engineering.The sphericity and surface finish uniformity of PAMS HCMs are critical for achieving highquality GDP fuel capsules.In this work,millimeter-scale PAMS HCMs were fabricated by a microencapsulation technique.The sphericity and surface finish uniformity were concurrently improved using di-t-butyl peroxide(DTBP).The mechanisms of these effects were also experimentally and theoretically investigated.The results show that DTBP distributes at the O-W2 interface of W1/O/W2 compound droplets,which resists the diffusion of molecules through the O-W2 interface bidirectionally.The resisted diffusion of H_(2)O molecules into the O phase eliminates PAMS HCM surface defects.Additionally,the resistance of fluorobenzene(FB)molecules from diffusing from the O phase into the W2 phase can effectively extend the solidification of W1/O/W2 compound droplets and thus improve the spherical uniformity of the HCMs.Using these improved PAMS HCMs,GDP fuel capsules meeting the stringent requirements for ICF engineering are prepared,and the quality of which is beyond the National Ignition Facility standard.展开更多
基金Project(2006AA04Z331)supported by the Hi-tech Research and Development Program of ChinaProject(50835002)supported by theKey Program of the National Natural Science Foundation of ChinaProject(JC-06-07)supported by the Science Foundation for Distinguished Young Scholars of Heilongjiang Province,China。
文摘Ion beam irradiation was adopted for surface treatment of the micro punch manufactured by precision machining.Ar plasma was used for the ion irradiation process,which was generated by the electron cyclotron resonance(ECR)equipment.The surface finish processes of micro punch were carried out at irradiation angles of 45°and 10°,respectively.The surface roughness and topography were measured to estimate the quality of surface finish.The results show that the ion irradiation is very effective to reduce the surface roughness,which can be improved more significantly at irradiation angle of 10°than at 45°.The technology of surface finish with ion beam irradiation is suitable for the surface treatment of micro die.
文摘Prediction of surface finish in turning process is a difficult but important task. Artificial Neural Networks (ANN) can reliably pred ict the surface finish but require a lot of training data. To overcome this prob lem, an expert system approach is proposed, wherein it will be possible to predi ct the surface finish from limited experiments. The expert system contains a kno wledge base prepared from machining data handbooks and number of experiments con ducted by turning steel rods, over a wide range of cutting parameters. With this knowledge base, the expert system predicts surface finish for different tool-w ork-piece combinations, by carrying out few experiments for each case. The prop osed expert system model is validated by carrying out a number of experiments.
文摘Metal framework composites have higher mechanical properties in examination to metals over an extensive variety of working conditions. This makes them an alluring alternative in swapping metals for different building applications. The present review is a study on the influence of composite titanium on the cutting parameters, mechanical behavior, reinforcements, structure and nanostructure. This review will provide an understanding into selecting the optimum machining parameters for machining titanium composites. It’s also an attempt to give brief explanation by suitably machining the titanium composite which can be made reasonable.
基金financially supported by the Sciences Platform Environment and Capacity Building Projects of GDAS(No.2021GDASYL-20210102005)the Guangdong Special Support Program(No.2019BT02C629)+2 种基金the GuangDong Basic and Applied Basic Research Foundation(Nos.2020A1515111031 and 2021A515010939)the Guangzhou Major Projects of Industry University-Research(IUR)Collaborative Innovation“Surface Treatment and Repair for Key Components of Industrial Gas Turbine(IGT).”support from the program of CSC(No.201801810066)support from the program of CSC(No.201801810106)。
文摘This work focuses on the structure and magnetic properties of Fe-50wt% Ni permalloy manufactured from the pre-alloyed powder by selective laser melting (SLM). The selective laser melted (SLMed) alloys were characterized by a 3D profilometer,optical microscope, scanning electron microscope, X-ray diffraction, etc. The effects of the volume energy density of laser(LVED) on structure, and magnetic properties with coercivity ( H), remanence ( B), and power losses ( P), were evaluated and discussed systematically. The results show that the relative porosity rate and the surface roughness of the SLMed specimens decreased with the increase in LVED. Only the γ-(FeNi) phase was detected in the X-ray diffraction patterns of the SLMed permalloys fabricated from the different LVEDs. Statistical analysis of optical microscopy images indicated that the grain coarsened at higher LVED. Furthermore, the microstructure of the SLMed parts was a typical columnar structure with an oriented growth of building direction. The highest microhardness reached 198 HV. Besides, the magnetic properties including B, H, and Pof SLMed samples decreased when the LVED ranged from 33.3 to 60.0 J/mm ~3 firstly and then increased while LVED further up to 93.3 J/mm, which is related to the decrease in porosity and the increase in grain size, while the higher residual stress and microcracks presented in the samples manufactured using very high LVED. The observed evolution of magnetic properties and LVED provides a good compromise in terms of reduced porosity and crack formation for the fabrication of SLMed Fe-50 wt% Ni permalloy. The theoretical mechanism in this study can offer guidance to further investigate SLMed soft magnetic alloys.
文摘The formation of a heterogeneous oxidized layer,also called scale,on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys.Partial or total removal of the scale represents a mandatory integrated step for the industrial fabrication processes of medical devices.For biodegradable metals,acid pickling has already been reported as a preliminary surface preparation given further processes,such as electropolishing.Unfortunately,biodegradable medical prototypes presented discrepancies concerning acid pickling studies based on samples with less complex geometry(e.g.,non-uniform scale removal and rougher surface).Indeed,this translational knowledge lacks a detailed investigation on this process,deep characterization of treated surfaces properties,as well as a comprehensive discussion of the involved mechanisms.In this study,the effects of different acidic media(HCl,HNO_(3),H_(3)PO_(4),CH_(3)COOH,H_(2)SO_(4) and HF),maintained at different temperatures(21 and 60℃)for various exposition time(15-240 s),on the chemical composition and surface properties of a Fe-13Mn-1.2C biodegradable alloy were investigated.Changes in mass loss,morphology and wettability evidenced the combined effect of temperature and time for all conditions.Pickling in HCl and HF solutions favor mass loss(0.03-0.1 g/cm^(2))and effectively remove the initial scale.
基金This work was supported by the National Natural Science Foundation of China(52036006,51725602 and 22002145)the Young Talents Program of Laser Fusion Research Center and the Open Project of State Key Laboratory of Environment-friendly Energy Materials(21kfhg03).
文摘Uniform poly-α-methylstyrene(PAMS)hollow core microcapsules(HCMs)are widely used as templates to fabricate glow discharge polymer(GDP)fuel capsules,which are fundamental devices for inertial confinement fusion(ICF)engineering.The sphericity and surface finish uniformity of PAMS HCMs are critical for achieving highquality GDP fuel capsules.In this work,millimeter-scale PAMS HCMs were fabricated by a microencapsulation technique.The sphericity and surface finish uniformity were concurrently improved using di-t-butyl peroxide(DTBP).The mechanisms of these effects were also experimentally and theoretically investigated.The results show that DTBP distributes at the O-W2 interface of W1/O/W2 compound droplets,which resists the diffusion of molecules through the O-W2 interface bidirectionally.The resisted diffusion of H_(2)O molecules into the O phase eliminates PAMS HCM surface defects.Additionally,the resistance of fluorobenzene(FB)molecules from diffusing from the O phase into the W2 phase can effectively extend the solidification of W1/O/W2 compound droplets and thus improve the spherical uniformity of the HCMs.Using these improved PAMS HCMs,GDP fuel capsules meeting the stringent requirements for ICF engineering are prepared,and the quality of which is beyond the National Ignition Facility standard.
