To increase the strength of the laser powder-bed fusion (LPBF) Al-Si-based aluminum alloy, TiB_(2) ceramic particles were selected to be mixed with high-Mg content Al-Si-Mg-Zr powder, and then a novel TiB_(2)/Al-Si-Mg...To increase the strength of the laser powder-bed fusion (LPBF) Al-Si-based aluminum alloy, TiB_(2) ceramic particles were selected to be mixed with high-Mg content Al-Si-Mg-Zr powder, and then a novel TiB_(2)/Al-Si-Mg-Zr composite was fabricated using LPBF. The results indicated that a dense sample with a maximum relative density of 99.85% could be obtained by adjusting the LPBF process parameters. Incorporating TiB_(2) nanoparticles enhanced the powder's laser absorption rate, thereby raising the alloy's intrinsic heat treatment temperature and consequently facilitating the precipitation of Si and βʺ nanoparticles in the α-Al cells. Moreover, the rapid cooling process during LPBF resulted in numerous alloying elements with low-stacking fault energy dissolving in the α-Al matrix, thus promoting the formation of the 9R phase. After a 48 h direct aging treatment at 150℃, the strength of the alloy slightly increased due to the increase of nanoprecipitates. Both yield strength and ultimate tensile strength of the LPBF TiB_(2)/Al-Si-Mg-Zr alloy were significantly higher than that of other LPBF TiB_(2)-modified aluminum alloys with external addition.展开更多
As a representative transition metal dichalcogenides(TMD),NiTe_(2)has an ultra-fast optical response,high carrier mobility,and excellent environmental stability.It has a broad application prospect in the fields of ene...As a representative transition metal dichalcogenides(TMD),NiTe_(2)has an ultra-fast optical response,high carrier mobility,and excellent environmental stability.It has a broad application prospect in the fields of ener-gy,biomedicine,optoelectronic devices,and so on.At present,there have been scant reports on the application of NiTe_(2)in the field of ultrafast photonics.In this work,NiTe_(2)was synthesized by chemical vapor deposition(CVD)and integrated with a tapered optical fiber to achieve mode-locking in an erbium-doped fiber laser(EDFL)and a thu-lium-doped fiber laser(TDFL).The mode-locked EDFL exhibited a pulse width of 678 fs and an output power of 3.92 mW.The pulse width of mode-locked TDFL was estimated to have a pulse width of 694 fs with an output power of 21.64 mW.These results demonstrate that NiTe_(2)is an effective saturable absorber material with potential applica-tions in the field of ultrafast optics.展开更多
Type-II Dirac semimetal PtTe2is a promising candidate for various electronic device applications due to its high carrier mobility,high conductivity,and air stability.In this work,we report on the growth of large-scale...Type-II Dirac semimetal PtTe2is a promising candidate for various electronic device applications due to its high carrier mobility,high conductivity,and air stability.In this work,we report on the growth of large-scale PtTe_(2)films by the pulsed laser deposition(PLD)and the comparison of the magnetotransport properties with the PtTe2films grown by the chemical vapor deposition(CVD).The low-temperature Hall curves of the PLD-grown films exhibit a linear behavior,in contrast with the nonlinear characteristic of the Hall behavior observed in CVD-grown films,in which a defect gradient is introduced.Meanwhile,both PtTe2films show weak antilocalization at low temperatures,which is attributed to the strong spin–orbit coupling.展开更多
The robustness of single-atom catalysts(SACs)is a critical concern for practical applications,especially for thermal catalysis at elevated temperatures under reductive conditions.In this study,a laser solid-phase synt...The robustness of single-atom catalysts(SACs)is a critical concern for practical applications,especially for thermal catalysis at elevated temperatures under reductive conditions.In this study,a laser solid-phase synthesis technique is reported to fabricate atom-nanoisland-sea structured SACs for the first time.The resultant catalysts are constructed by Pt single atoms on In_(2)O_(3)supported by Co3O4nanoislands uniformly dispersed in the sea of reduced graphene oxide.The laser process,with a maximum temperature of 2349 K within~100μs,produced abundant oxygen vacancies(up to 70.8%)and strong interactions between the Pt single atoms and In_(2)O_(3).The laser-synthesized catalysts exhibited a remarkable catalytic performance towards CO_(2)hydrogenation to methanol at 300°C with a CO_(2)conversion of 30.3%,methanol selectivity of 90.6%and exceptional stability over 48 h without any deactivation,outperforming most of the relevant catalysts reported in the literature.Characterization of the spent catalysts after testing for 48 h reveals that the Pt single atoms were retained and the oxygen vacancies remained almost unchanged.In situ diffuse reflectance infrared Fourier transform spectrum was conducted to establish the reaction mechanism supported by the density functional theory simulations.It is believed that this laser synthesis strategy opens a new avenue towards rapidly manufacturing highly active and robust thermal SACs.展开更多
The electrochemical conversion of CO_(2) into value-added chemicals presents an environmentally sustainable alternative to conventional fossil-derived processes,yet achieving high selectivity remains challenging due t...The electrochemical conversion of CO_(2) into value-added chemicals presents an environmentally sustainable alternative to conventional fossil-derived processes,yet achieving high selectivity remains challenging due to competing reaction pathways.Here,we demonstrate precise tuning of CO_(2) electroreduction pathways through femtosecond laser-driven surface doping of Cu with targeted metals,achieving Faradaic efficiencies of 58.9%for CO,67.9%for formate,and 37.8%for ethylene.This spatially shaping laser technique enables nanoscale deposition of any metal(including Sb,Sn,Re,La,In,Co,Ni,Ag,and Pt)onto Cu foil,forming compositionally graded Cu-based bimetallic surfaces with controlled atomic ratios.Systematic electronic structure analysis reveals that secondary metals induce d-band center shifts spanning−0.21 to+0.78 eV,governing intermediate adsorption energetics-upward shifts strengthen*CO binding via enhanced back-donation,while downward shifts generally weaken adsorbate interactions.Through precise control of Cu/Sn and Cu/Sb atomic ratios,we manipulate electronic structures of CuSn and CuSb catalysts and consequently demonstrate continuous tuning of formate(19.0%-67.9%)and CO(18.8%-58.9%)selectivity.In-situ Raman spectroscopy and valence band X-ray photoelectron spectroscopy(XPS)elucidate dual modulation mechanisms.Sn enhances CO desorption by weakening*CO adsorption,whereas La promotes ethylene formation through optimized CO absorption and dimerization.The tunability of the reaction pathways aligns with metal-dependent stabilization of critical intermediates(CO and*OCHO).This work introduces a nanoscale-depth and trace-level multi-elemental loading strategy with tunable ratios on copper electrodes,enabling precise electronic structure manipulation of Cu-based electrocatalysts to mechanistically elucidate the correlation between surface electronic states and product selectivity,offering a roadmap to design and modulate Cu-based catalysts for selective CO_(2)-to-chemical conversion and beyond via low-cost laser processing techniques.展开更多
To solve the problems of deformation,micro-cracks,and residual tensile stress in laser cladding coatings,the technique of laser cladding with Fe-based memory alloy can be considered.However,the process of in-situ synt...To solve the problems of deformation,micro-cracks,and residual tensile stress in laser cladding coatings,the technique of laser cladding with Fe-based memory alloy can be considered.However,the process of in-situ synthesis of Fe-based memory alloy coatings is extremely complex.At present,there is no clear guidance scheme for its preparation process,which limits its promotion and application to some extent.Therefore,in this study,response surface methodology(RSM)was used to model the response surface between the target values and the cladding process parameters.The NSGA-2 algorithm was employed to optimize the process parameters.The results indicate that the composite optimization method consisting of RSM and the NSGA-2 algorithm can establish a more accurate model,with an error of less than 4.5%between the predicted and actual values.Based on this established model,the optimal scheme for process parameters corresponding to different target results can be rapidly obtained.The prepared coating exhibits a uniform structure,with no defects such as pores,cracks,and deformation.The surface roughness and microhardness of the coating are enhanced,the shaping quality of the coating is effectively improved,and the electrochemical corrosion performance of the coating in 3.5%NaCl solution is obviously better than that of the substrate,providing an important guide for engineering applications.展开更多
Phosphor-in-glass(PiG)has been prepared into various types of phosphor films owing to its simplicity process,exceptional color purity,and convenient color adjustability.Nevertheless,existing reflective PiGs films have...Phosphor-in-glass(PiG)has been prepared into various types of phosphor films owing to its simplicity process,exceptional color purity,and convenient color adjustability.Nevertheless,existing reflective PiGs films have encountered limitations in terms of stability and feasibility as reliable color converters,mainly attributed to issues related to thermal deposition and insufficient optical efficiency.Herein,we propose to use AlN substrate with superior thermal conductivity to coat the TiO_(2) layer to obtain TiO_(2)-AlN(TA),which enhances the reflectivity of blue light to facilitate the light conversion process.By incorporating highly thermally stable LuAG:Ce-PiGs on a TA substrate,the LuAG:Ce-PiTA converter exhibits a luminous flux of 1102 lm@6.4 W,and maintains a relative intensity of 94.6%at 473 K benefiting from the high thermal conductivity of 34.1 W/(m·K).The addition of CASN_(3):Eu to the color converter 50 L&10C-PiTA enables an impressive CRI of 90.7.Relative lumine scence intensities of LuAG:Ce-PiTA and 50 L&10C-PiTA only decrease by 5.35%and 3.28%,respectively,in the 24 h illumination aging decay test of the reflective laser module.The results confirm the suitability of the optimally designed TA substrate for LuAG:Ce color converter applications in high-power reflective laser illumination.展开更多
Improving the high-temperature performance of Inconel 718(IN718)alloys manufactured via laser powder bed fusion(LPBF)has been the most concerned issue in the industry.In this study,the effects of Ti_(2)AlC inoculants ...Improving the high-temperature performance of Inconel 718(IN718)alloys manufactured via laser powder bed fusion(LPBF)has been the most concerned issue in the industry.In this study,the effects of Ti_(2)AlC inoculants on microstructures and high-temperature mechanical properties of the as-built IN718 composites were investigated.According to statistical results of relative density and unmelted particle area in as-built alloys,the optimal energy of 112 J/mm^(3)was determined.It was observed that the precipitation of the MC carbide was significantly enhanced with the addition of Ti_(2)AlC,restricting the precipitation of the Laves phase.The MC particles were uniformly distributed along the subgrain boundaries,which contributed to the dispersion strengthening.Meanwhile,the MC particles served as nucleation sites for heterogeneous nucleation during the solidification process,facilitating the refinement of columnar and cellular grains.The simulated Scheil-Gulliver curves showed that the precipitation sequence of phases did not change with Ti_(2)AlC inoculants.The as-built 1%Ti_(2)AlC/IN718 sample demonstrated an ultimate tensile strength of 998.78 MPa and an elongation of 18.04%at 650℃,revealing a markedly improved mechanical performance compared with the LPBF-manufactured IN718 alloys.The high-temperature tensile strength of 1%Ti_(2)AlC/IN718 sample increased to 1197.99 MPa by heat treatment.It was suggested that dislocation strengthening and ordered strengthening were two most important reinforcement mechanisms.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51801079 and 52001140)the National Science Centre,Poland(Narodowe Centrum Nauki)(No.UMO-2021/42/E/ST5/00339).
文摘To increase the strength of the laser powder-bed fusion (LPBF) Al-Si-based aluminum alloy, TiB_(2) ceramic particles were selected to be mixed with high-Mg content Al-Si-Mg-Zr powder, and then a novel TiB_(2)/Al-Si-Mg-Zr composite was fabricated using LPBF. The results indicated that a dense sample with a maximum relative density of 99.85% could be obtained by adjusting the LPBF process parameters. Incorporating TiB_(2) nanoparticles enhanced the powder's laser absorption rate, thereby raising the alloy's intrinsic heat treatment temperature and consequently facilitating the precipitation of Si and βʺ nanoparticles in the α-Al cells. Moreover, the rapid cooling process during LPBF resulted in numerous alloying elements with low-stacking fault energy dissolving in the α-Al matrix, thus promoting the formation of the 9R phase. After a 48 h direct aging treatment at 150℃, the strength of the alloy slightly increased due to the increase of nanoprecipitates. Both yield strength and ultimate tensile strength of the LPBF TiB_(2)/Al-Si-Mg-Zr alloy were significantly higher than that of other LPBF TiB_(2)-modified aluminum alloys with external addition.
基金Supported by Guangdong Basic and Applied Basic Research Fund,China(2024A1515012429)。
文摘As a representative transition metal dichalcogenides(TMD),NiTe_(2)has an ultra-fast optical response,high carrier mobility,and excellent environmental stability.It has a broad application prospect in the fields of ener-gy,biomedicine,optoelectronic devices,and so on.At present,there have been scant reports on the application of NiTe_(2)in the field of ultrafast photonics.In this work,NiTe_(2)was synthesized by chemical vapor deposition(CVD)and integrated with a tapered optical fiber to achieve mode-locking in an erbium-doped fiber laser(EDFL)and a thu-lium-doped fiber laser(TDFL).The mode-locked EDFL exhibited a pulse width of 678 fs and an output power of 3.92 mW.The pulse width of mode-locked TDFL was estimated to have a pulse width of 694 fs with an output power of 21.64 mW.These results demonstrate that NiTe_(2)is an effective saturable absorber material with potential applica-tions in the field of ultrafast optics.
基金Project supported by the National Key R&D Program of China(Grant No.2022YFA1402404)the National Natural Science Foundation of China(Grant Nos.T2394473,624B2070,and 62274085)。
文摘Type-II Dirac semimetal PtTe2is a promising candidate for various electronic device applications due to its high carrier mobility,high conductivity,and air stability.In this work,we report on the growth of large-scale PtTe_(2)films by the pulsed laser deposition(PLD)and the comparison of the magnetotransport properties with the PtTe2films grown by the chemical vapor deposition(CVD).The low-temperature Hall curves of the PLD-grown films exhibit a linear behavior,in contrast with the nonlinear characteristic of the Hall behavior observed in CVD-grown films,in which a defect gradient is introduced.Meanwhile,both PtTe2films show weak antilocalization at low temperatures,which is attributed to the strong spin–orbit coupling.
基金supported by the Ningbo Yongjiang Science and Technology Programme(2023A-161-C)。
文摘The robustness of single-atom catalysts(SACs)is a critical concern for practical applications,especially for thermal catalysis at elevated temperatures under reductive conditions.In this study,a laser solid-phase synthesis technique is reported to fabricate atom-nanoisland-sea structured SACs for the first time.The resultant catalysts are constructed by Pt single atoms on In_(2)O_(3)supported by Co3O4nanoislands uniformly dispersed in the sea of reduced graphene oxide.The laser process,with a maximum temperature of 2349 K within~100μs,produced abundant oxygen vacancies(up to 70.8%)and strong interactions between the Pt single atoms and In_(2)O_(3).The laser-synthesized catalysts exhibited a remarkable catalytic performance towards CO_(2)hydrogenation to methanol at 300°C with a CO_(2)conversion of 30.3%,methanol selectivity of 90.6%and exceptional stability over 48 h without any deactivation,outperforming most of the relevant catalysts reported in the literature.Characterization of the spent catalysts after testing for 48 h reveals that the Pt single atoms were retained and the oxygen vacancies remained almost unchanged.In situ diffuse reflectance infrared Fourier transform spectrum was conducted to establish the reaction mechanism supported by the density functional theory simulations.It is believed that this laser synthesis strategy opens a new avenue towards rapidly manufacturing highly active and robust thermal SACs.
基金supported by the National Key R&D Program of China(No.2022YFB4601300)Aeronautical Science Fund(No.3030021252404)+2 种基金the National Natural Science Foundation of China(NSFC,No.52475425)the NSFC Basic Sciences Center Program(Extreme Light Field Manufacturing,No.52488301)We thank the Analytical&Testing Center of Beijing Institute of Technology for providing XPS and valence band measurements.We thank the BL02B01 and BL01B Beamlines at Shanghai Synchrotron Radiation Facility(SSRF),supported by the NSFC(No.11227902),for photoelectron spectroscopy and vibrational spectroscopy studies.We thank the support from beamline BL11U and BL10B at the National Synchrotron Radiation Laboratory(NSRL)in Hefei,China,for the synchrotron radiation and X-ray spectroscopic measurements.
文摘The electrochemical conversion of CO_(2) into value-added chemicals presents an environmentally sustainable alternative to conventional fossil-derived processes,yet achieving high selectivity remains challenging due to competing reaction pathways.Here,we demonstrate precise tuning of CO_(2) electroreduction pathways through femtosecond laser-driven surface doping of Cu with targeted metals,achieving Faradaic efficiencies of 58.9%for CO,67.9%for formate,and 37.8%for ethylene.This spatially shaping laser technique enables nanoscale deposition of any metal(including Sb,Sn,Re,La,In,Co,Ni,Ag,and Pt)onto Cu foil,forming compositionally graded Cu-based bimetallic surfaces with controlled atomic ratios.Systematic electronic structure analysis reveals that secondary metals induce d-band center shifts spanning−0.21 to+0.78 eV,governing intermediate adsorption energetics-upward shifts strengthen*CO binding via enhanced back-donation,while downward shifts generally weaken adsorbate interactions.Through precise control of Cu/Sn and Cu/Sb atomic ratios,we manipulate electronic structures of CuSn and CuSb catalysts and consequently demonstrate continuous tuning of formate(19.0%-67.9%)and CO(18.8%-58.9%)selectivity.In-situ Raman spectroscopy and valence band X-ray photoelectron spectroscopy(XPS)elucidate dual modulation mechanisms.Sn enhances CO desorption by weakening*CO adsorption,whereas La promotes ethylene formation through optimized CO absorption and dimerization.The tunability of the reaction pathways aligns with metal-dependent stabilization of critical intermediates(CO and*OCHO).This work introduces a nanoscale-depth and trace-level multi-elemental loading strategy with tunable ratios on copper electrodes,enabling precise electronic structure manipulation of Cu-based electrocatalysts to mechanistically elucidate the correlation between surface electronic states and product selectivity,offering a roadmap to design and modulate Cu-based catalysts for selective CO_(2)-to-chemical conversion and beyond via low-cost laser processing techniques.
基金financial supports from the National Natural Science Foundation of China-Youth Project(51801076)the Provincial Colleges and Universities Natural Science Research Project of Jiangsu Province(18KJB430009)+1 种基金the Postdoctoral Research Support Project of Jiangsu Province(1601055C)the Senior Talents Research Startup of Jiangsu University(14JDG126)。
文摘To solve the problems of deformation,micro-cracks,and residual tensile stress in laser cladding coatings,the technique of laser cladding with Fe-based memory alloy can be considered.However,the process of in-situ synthesis of Fe-based memory alloy coatings is extremely complex.At present,there is no clear guidance scheme for its preparation process,which limits its promotion and application to some extent.Therefore,in this study,response surface methodology(RSM)was used to model the response surface between the target values and the cladding process parameters.The NSGA-2 algorithm was employed to optimize the process parameters.The results indicate that the composite optimization method consisting of RSM and the NSGA-2 algorithm can establish a more accurate model,with an error of less than 4.5%between the predicted and actual values.Based on this established model,the optimal scheme for process parameters corresponding to different target results can be rapidly obtained.The prepared coating exhibits a uniform structure,with no defects such as pores,cracks,and deformation.The surface roughness and microhardness of the coating are enhanced,the shaping quality of the coating is effectively improved,and the electrochemical corrosion performance of the coating in 3.5%NaCl solution is obviously better than that of the substrate,providing an important guide for engineering applications.
文摘Phosphor-in-glass(PiG)has been prepared into various types of phosphor films owing to its simplicity process,exceptional color purity,and convenient color adjustability.Nevertheless,existing reflective PiGs films have encountered limitations in terms of stability and feasibility as reliable color converters,mainly attributed to issues related to thermal deposition and insufficient optical efficiency.Herein,we propose to use AlN substrate with superior thermal conductivity to coat the TiO_(2) layer to obtain TiO_(2)-AlN(TA),which enhances the reflectivity of blue light to facilitate the light conversion process.By incorporating highly thermally stable LuAG:Ce-PiGs on a TA substrate,the LuAG:Ce-PiTA converter exhibits a luminous flux of 1102 lm@6.4 W,and maintains a relative intensity of 94.6%at 473 K benefiting from the high thermal conductivity of 34.1 W/(m·K).The addition of CASN_(3):Eu to the color converter 50 L&10C-PiTA enables an impressive CRI of 90.7.Relative lumine scence intensities of LuAG:Ce-PiTA and 50 L&10C-PiTA only decrease by 5.35%and 3.28%,respectively,in the 24 h illumination aging decay test of the reflective laser module.The results confirm the suitability of the optimally designed TA substrate for LuAG:Ce color converter applications in high-power reflective laser illumination.
基金supported by the National Natural Science Foundation of China(Nos.52374396 and 52122409).
文摘Improving the high-temperature performance of Inconel 718(IN718)alloys manufactured via laser powder bed fusion(LPBF)has been the most concerned issue in the industry.In this study,the effects of Ti_(2)AlC inoculants on microstructures and high-temperature mechanical properties of the as-built IN718 composites were investigated.According to statistical results of relative density and unmelted particle area in as-built alloys,the optimal energy of 112 J/mm^(3)was determined.It was observed that the precipitation of the MC carbide was significantly enhanced with the addition of Ti_(2)AlC,restricting the precipitation of the Laves phase.The MC particles were uniformly distributed along the subgrain boundaries,which contributed to the dispersion strengthening.Meanwhile,the MC particles served as nucleation sites for heterogeneous nucleation during the solidification process,facilitating the refinement of columnar and cellular grains.The simulated Scheil-Gulliver curves showed that the precipitation sequence of phases did not change with Ti_(2)AlC inoculants.The as-built 1%Ti_(2)AlC/IN718 sample demonstrated an ultimate tensile strength of 998.78 MPa and an elongation of 18.04%at 650℃,revealing a markedly improved mechanical performance compared with the LPBF-manufactured IN718 alloys.The high-temperature tensile strength of 1%Ti_(2)AlC/IN718 sample increased to 1197.99 MPa by heat treatment.It was suggested that dislocation strengthening and ordered strengthening were two most important reinforcement mechanisms.
