Multi-layer laser cladding manufacturing is a newly developed rapid manufacturing technology. It is a powerful tool for direct fabrication of three-dimensional fully dense metal components and part repairing. In this ...Multi-layer laser cladding manufacturing is a newly developed rapid manufacturing technology. It is a powerful tool for direct fabrication of three-dimensional fully dense metal components and part repairing. In this paper, the microstructure evolution and properties of 316L stainless steel deposited with this technology was investigated, compact components with properties similar to the as-cast and wrought annealed material was obtained. Cracking was eliminated by introducing of supersonic vibration and application of parameter adjustment technologies.展开更多
This work investigated the gradient microstructure evolution and tensile property of LPBF fabricated 15-5 precipitation hardening stainless steel in post-process direct ageing(DA)and solution treating&ageing(STA)....This work investigated the gradient microstructure evolution and tensile property of LPBF fabricated 15-5 precipitation hardening stainless steel in post-process direct ageing(DA)and solution treating&ageing(STA).The varied microstructures for austenite and small-sized oxide inclusions at different sample heights in the as-built(AB)condition was generally preserved after DA treatment.However,austenite was almost disappeared,and oxide particle grew significantly after the STA treatment.As a result,the tensile property differences in sample top and bottom for AB and DA conditions did not occur in the STA samples.For the influence of post-process heat treatment,the STA condition had the highest yield strength due to the highest volume fraction of nano-sized Cu precipitates.However,the DA specimen had the highest ultimate tensile strength and elongation owing to the considerable amount of austenite phase and associated transformation induced plasticity effect.展开更多
Laser powder bed fusion (LPBF) is a commonly used additive manufacturing (AM) method for efficiently producing intricate geometric components. This investigation examines factors such as pores, cellular structure, gra...Laser powder bed fusion (LPBF) is a commonly used additive manufacturing (AM) method for efficiently producing intricate geometric components. This investigation examines factors such as pores, cellular structure, grain size, and inclusions from the manufacturing process that contribute to the corrosion resistance of LPBF DSS. Furthermore, the as-built LPBF duplex stainless steel (DSS) is primarily ferrite due to the rapid cooling process. Therefore, the transformation of ferrite to austenite after various heat treatments in LPBF DSS and its corresponding corrosion resistance are presented. Additionally, a new mixed powder method is proposed to increase the austenite content in the as-built LPBF DSS. This review also focuses on the passivation capability and pitting corrosion performance in LPBF and conventional DSS. This article summarizes the variations in microstructure between as-built and heat-treated LPBF DSS, with their impacts on corrosion resistance, offering insights for manufacturing highly corrosion-resistant LPBF DSS.展开更多
3D metal printing process has attracted increasing attention in recent years due to advantages,such as flexibility and rapid prototyping.This study aims to investigate the orientation effect of electropolishing charac...3D metal printing process has attracted increasing attention in recent years due to advantages,such as flexibility and rapid prototyping.This study aims to investigate the orientation effect of electropolishing characteristics on different surfaces of 316L stainless steel fabricated by laser powder bed fusion(L-PBF),considering that the rough surface of 3D printed parts is a key factor limiting its applications in the industry.The electropolishing characteristics on the different surfaces corresponding to the building orientation in selective laser melting are studied.Experimental results show that electrolyte temperature has critical importance on the electropolishing,especially for the vertical direction to the layering plane.The finish of electropolished surfaces is affected by the defects generated during L-PBF process.Thus,the electropolished vertical surface has higher surface roughness Sa than the horizontal surface.The X-ray photoelectron spectroscopy spectra show that the electropolished horizontal surface has higher Cr/Fe element ratio than the vertical surface.The electropolished horizontal surface presents higher corrosion resistance than the vertical surface by measuring the anodic polarization curves and fitting the equivalent circuit of experimental electrochemical impedance spectroscopy.展开更多
CO2 laser is employed to join a piece of powder metallurgical material （PMM） to a stainless steel in butt joint welding mode. The powder Ni35, as a filler powder, is used. The weld metal comes from three parts of st...CO2 laser is employed to join a piece of powder metallurgical material （PMM） to a stainless steel in butt joint welding mode. The powder Ni35, as a filler powder, is used. The weld metal comes from three parts of stainless steel, powder Ni35, and Cu in W-Cu PMM. It is indicated that some parts of the W-Cu base metal are heated by laser and the metal Cu at the width of 0.06--0.12 mm from the edge is melted into the melting pool in the laser welding process. The formation of firm weld joint is just because that the melting liquid metal could fill the position occupied by metal Cu and surround the metal W granules fully. The analysis results indicate that the mechanism of the laser welding for stainless steel and W-Cu alloy is a special mode of fusion-brazing welding.展开更多
基金supported by the National Natural Science Foundation of China under the Grant No.50375096
文摘Multi-layer laser cladding manufacturing is a newly developed rapid manufacturing technology. It is a powerful tool for direct fabrication of three-dimensional fully dense metal components and part repairing. In this paper, the microstructure evolution and properties of 316L stainless steel deposited with this technology was investigated, compact components with properties similar to the as-cast and wrought annealed material was obtained. Cracking was eliminated by introducing of supersonic vibration and application of parameter adjustment technologies.
基金Sheng Cao thanks the support from the National Natural Science Foundation of China(No.52204391)the Special Fund Project for Science and Technology Innovation Strategy of Guangdong Province(Nos.STKJ202209021 and STKJ2023040)+1 种基金the Characteristic Innovation Project(Natural Science)for Regular University in Guangdong Province(No.2022KTSCX038)the Shantou University Research Foundation for Talents(No.NTF21013).
文摘This work investigated the gradient microstructure evolution and tensile property of LPBF fabricated 15-5 precipitation hardening stainless steel in post-process direct ageing(DA)and solution treating&ageing(STA).The varied microstructures for austenite and small-sized oxide inclusions at different sample heights in the as-built(AB)condition was generally preserved after DA treatment.However,austenite was almost disappeared,and oxide particle grew significantly after the STA treatment.As a result,the tensile property differences in sample top and bottom for AB and DA conditions did not occur in the STA samples.For the influence of post-process heat treatment,the STA condition had the highest yield strength due to the highest volume fraction of nano-sized Cu precipitates.However,the DA specimen had the highest ultimate tensile strength and elongation owing to the considerable amount of austenite phase and associated transformation induced plasticity effect.
基金supported by the National Natural Science Foundation of China(No.U22B2065)the Science and Technology Fundamental Resources Investigation Program(No.2022FY10300).
文摘Laser powder bed fusion (LPBF) is a commonly used additive manufacturing (AM) method for efficiently producing intricate geometric components. This investigation examines factors such as pores, cellular structure, grain size, and inclusions from the manufacturing process that contribute to the corrosion resistance of LPBF DSS. Furthermore, the as-built LPBF duplex stainless steel (DSS) is primarily ferrite due to the rapid cooling process. Therefore, the transformation of ferrite to austenite after various heat treatments in LPBF DSS and its corresponding corrosion resistance are presented. Additionally, a new mixed powder method is proposed to increase the austenite content in the as-built LPBF DSS. This review also focuses on the passivation capability and pitting corrosion performance in LPBF and conventional DSS. This article summarizes the variations in microstructure between as-built and heat-treated LPBF DSS, with their impacts on corrosion resistance, offering insights for manufacturing highly corrosion-resistant LPBF DSS.
基金This publication has emanated from research supported in part by a grant from Science Foundation Ireland under Grant No.15/RP/B3208For the purpose of Open Access,the author has applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submissionThis project has also received funding from the Enterprise Ireland and the European Union's Horizon 2020 Research and Innovation Program under the Marie Sklodowska-Curie Grant agreement No.713654.
文摘3D metal printing process has attracted increasing attention in recent years due to advantages,such as flexibility and rapid prototyping.This study aims to investigate the orientation effect of electropolishing characteristics on different surfaces of 316L stainless steel fabricated by laser powder bed fusion(L-PBF),considering that the rough surface of 3D printed parts is a key factor limiting its applications in the industry.The electropolishing characteristics on the different surfaces corresponding to the building orientation in selective laser melting are studied.Experimental results show that electrolyte temperature has critical importance on the electropolishing,especially for the vertical direction to the layering plane.The finish of electropolished surfaces is affected by the defects generated during L-PBF process.Thus,the electropolished vertical surface has higher surface roughness Sa than the horizontal surface.The X-ray photoelectron spectroscopy spectra show that the electropolished horizontal surface has higher Cr/Fe element ratio than the vertical surface.The electropolished horizontal surface presents higher corrosion resistance than the vertical surface by measuring the anodic polarization curves and fitting the equivalent circuit of experimental electrochemical impedance spectroscopy.
基金This work was supported by the Nature Science Fund of Beijing.
文摘CO2 laser is employed to join a piece of powder metallurgical material （PMM） to a stainless steel in butt joint welding mode. The powder Ni35, as a filler powder, is used. The weld metal comes from three parts of stainless steel, powder Ni35, and Cu in W-Cu PMM. It is indicated that some parts of the W-Cu base metal are heated by laser and the metal Cu at the width of 0.06--0.12 mm from the edge is melted into the melting pool in the laser welding process. The formation of firm weld joint is just because that the melting liquid metal could fill the position occupied by metal Cu and surround the metal W granules fully. The analysis results indicate that the mechanism of the laser welding for stainless steel and W-Cu alloy is a special mode of fusion-brazing welding.
