Multi-material laser powder bed fusion(LPBF)additive manufacturing is a promising approach for integrating the functionality and mechanical performance of dissimilar materials into complex parts.This review offers a c...Multi-material laser powder bed fusion(LPBF)additive manufacturing is a promising approach for integrating the functionality and mechanical performance of dissimilar materials into complex parts.This review offers a comprehensive overview of the recent advancements in multi-material LPBF,with a particular focus on compositionally heterogeneous/gradient parts and their fabrication methods and equipment,control of interfacial defects,innovative designs,and potential applications.It commences with the introduction of LPBF-processed compositionally heterogeneous/gradient structures with dissimilar material distributions,including Z-direction compositionally heterogeneous structures,compositionally gradient structures in the Z-direction and XY planes,and three-dimensional(3D)compositionally heterogeneous structures.Subsequently,various LPBF methods and equipment for fabricating compositionally heterogeneous/gradient structures have been presented.Furthermore,the interfacial defects and process control during LPBF for these types of compositionally heterogeneous/gradient structures are discussed.Additionally,innovative designs and potential applications of parts made from compositionally heterogeneous/gradient structures are illustrated.Finally,perspectives on the LPBF fabrication methods for compositionally heterogeneous/gradient structures are highlighted to provide guidance for future research.展开更多
It has always been challenging work to reconcile the contradiction between the strength and plasticity of titanium materials.Laser powder bed fusion(LPBF) is a convenient method to fabricate innovative composites incl...It has always been challenging work to reconcile the contradiction between the strength and plasticity of titanium materials.Laser powder bed fusion(LPBF) is a convenient method to fabricate innovative composites including those inspired by gradient layered materials.In this work,we used LPBF to selectively prepare Ti N/Ti gradient layered structure(GLSTi)composites by using different N_(2)–Ar ratios during the LPBF process.We systematically investigated the mechanisms of in-situ synthesis Ti N,high strength and ductility of GLSTi composites using microscopic analysis,TEM characterization,and tensile testing with digital image correlation.Besides,a digital correspondence was established between the N_(2) concentration and the volume fraction of LPBF in-situ synthesized Ti N.Our results show that the GLSTi composites exhibit superior mechanical properties compared to pure titanium fabricated by LPBF under pure Ar.Specifically,the tensile strength of GLSTi was more than 1.5times higher than that of LPBF-formed pure titanium,reaching up to 1100 MPa,while maintaining a high elongation at fracture of 17%.GLSTi breaks the bottleneck of high strength but low ductility exhibited by conventional nanoceramic particle-strengthened titanium matrix composites,and the hetero-deformation induced strengthening effect formed by the Ti N/Ti layered structure explained its strength-plasticity balanced principle.The microhardness exhibits a jagged variation of the relatively low hardness of 245 HV0.2 for the pure titanium layer and a high hardness of 408 HV0.2 for the N_(2) in-situ synthesis layer.Our study provides a new concept for the structure-performance digital customization of 3D-printed Ti-based composites.展开更多
Additive manufacturing of Al-Mg-Sc-Zr alloys is a promising technique for the fabrication of lightweight components with complex shapes.In this study,the effect of the process parameters of selective laser melting(SLM...Additive manufacturing of Al-Mg-Sc-Zr alloys is a promising technique for the fabrication of lightweight components with complex shapes.In this study,the effect of the process parameters of selective laser melting(SLM)on the surface morphology,relative density,microstructure,and mechanical properties of Al-Mg-Sc-Zr high-strength aluminum alloys with low Sc content was systematically investigated.The results show that the energy density has an important effect on the surface quality and densification behavior of the Al-Mg-Sc-Zr alloy during the SLM process.As the energy density increased,the surface quality and the number of internal pores increased.However,the area of the fine-grained region at the boundary of the molten pool gradually decreased.When the laser energy density was set to 151.52 J/mm3,a low-defect sample with a relative density of 99.2%was obtained.After heat treatment,the area of the fine grains at the boundary increased significantly,thereby contributing to the excellent mechanical properties.The microstructure was characterized by a unique“fan-shaped”heterogeneous structure.As the energy density increased,the microhardness first increased and then decreased,reaching a maximum value of 122 HV0.3.With the optimized process parameters,the yield strength(YS),ultimate tensile strength(UTS),and elongation of the as-built Al-Mg-Sc-Zr alloys were 346.8±3.0 MPa,451.1±5.2 MPa,14.6%±0.8%,respectively.After heat treatment at 325°C for 8 h,the hardness increased by 38.5%to 169 HV0.3,and the YS and UTS increased by 41.3%and 18.1%,respectively,to 490.0±9.0 MPa and 532.7±7.8 MPa,respectively,while the elongation slightly decreased to 13.1%±0.7%.展开更多
Laser powder bed fusion(LPBF)is an innovative method for manufacturing multimaterial components with high geometrical resolution.The LPBF-printing sequences of materials may be diverse in the actual design and applica...Laser powder bed fusion(LPBF)is an innovative method for manufacturing multimaterial components with high geometrical resolution.The LPBF-printing sequences of materials may be diverse in the actual design and application of multimaterial components.In this study,multimaterial copper(CuSn10)–steel(316 L)structures are printed using different building strategies(printing 316 L on CuSn10 and printing CuSn10 on 316 L)via LPBF,and the characteristics of two interfaces(the 316 L/CuSn10 or“L/C”and CuSn10/316 L or“C/L”interfaces)are investigated.Subsequently,the interfacial melting mode and formation mechanisms are discussed.At the L/C interface,the keyhole melting mode induced by the high volumetric energy density(EL/C=319.4 J/mm3)results in a large penetration depth in the pre-solidified layer and enhances laser energy absorption,thus promoting the extensive migration of materials and intense intermixing of elements to form a wide diffusion zone(∼400μm).At the C/L interface,the conduction mode induced by the low volumetric energy density(EC/L=74.1 J/mm3)results in a narrow diffusion zone(∼160μm).The interfacial defects observed are primarily cracks and pores.More cracks appeared at the C/L interface,which is attributable to the weak bonding strength of the narrow diffusion zone.This study provides guidance and reference for the design and manufacturing of multimaterial components via LPBF using different building strategies.展开更多
基金supported by the following projects:the National Key Research and Development Program of China(Nos.2022YFB4600303,and 2024YFB4608200)Guangdong Basic and Applied Basic Research Foundation(Nos.2022B1515020064,and 2022B1515120025)+2 种基金National Natural Science Foundation of China(Nos.52073105,and 52305358)the Fundamental Research Funds for the Central Universities(2024ZYGXZR079)Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)。
文摘Multi-material laser powder bed fusion(LPBF)additive manufacturing is a promising approach for integrating the functionality and mechanical performance of dissimilar materials into complex parts.This review offers a comprehensive overview of the recent advancements in multi-material LPBF,with a particular focus on compositionally heterogeneous/gradient parts and their fabrication methods and equipment,control of interfacial defects,innovative designs,and potential applications.It commences with the introduction of LPBF-processed compositionally heterogeneous/gradient structures with dissimilar material distributions,including Z-direction compositionally heterogeneous structures,compositionally gradient structures in the Z-direction and XY planes,and three-dimensional(3D)compositionally heterogeneous structures.Subsequently,various LPBF methods and equipment for fabricating compositionally heterogeneous/gradient structures have been presented.Furthermore,the interfacial defects and process control during LPBF for these types of compositionally heterogeneous/gradient structures are discussed.Additionally,innovative designs and potential applications of parts made from compositionally heterogeneous/gradient structures are illustrated.Finally,perspectives on the LPBF fabrication methods for compositionally heterogeneous/gradient structures are highlighted to provide guidance for future research.
基金supported by the Guangdong Basic and Applied Basic Research Foundation (2020B1515120013,2022B1515120066)National Natural Science Foundation of China (Nos.U2001218, 51875215)+1 种基金Key-Area Research and Development Program of Guangdong Province (2020B090923001)Special Support Foundation of Guangdong Province (No.2019TQ05Z110)。
文摘It has always been challenging work to reconcile the contradiction between the strength and plasticity of titanium materials.Laser powder bed fusion(LPBF) is a convenient method to fabricate innovative composites including those inspired by gradient layered materials.In this work,we used LPBF to selectively prepare Ti N/Ti gradient layered structure(GLSTi)composites by using different N_(2)–Ar ratios during the LPBF process.We systematically investigated the mechanisms of in-situ synthesis Ti N,high strength and ductility of GLSTi composites using microscopic analysis,TEM characterization,and tensile testing with digital image correlation.Besides,a digital correspondence was established between the N_(2) concentration and the volume fraction of LPBF in-situ synthesized Ti N.Our results show that the GLSTi composites exhibit superior mechanical properties compared to pure titanium fabricated by LPBF under pure Ar.Specifically,the tensile strength of GLSTi was more than 1.5times higher than that of LPBF-formed pure titanium,reaching up to 1100 MPa,while maintaining a high elongation at fracture of 17%.GLSTi breaks the bottleneck of high strength but low ductility exhibited by conventional nanoceramic particle-strengthened titanium matrix composites,and the hetero-deformation induced strengthening effect formed by the Ti N/Ti layered structure explained its strength-plasticity balanced principle.The microhardness exhibits a jagged variation of the relatively low hardness of 245 HV0.2 for the pure titanium layer and a high hardness of 408 HV0.2 for the N_(2) in-situ synthesis layer.Our study provides a new concept for the structure-performance digital customization of 3D-printed Ti-based composites.
基金Guangdong Provincial Key Field Research and Development Program Project of China(Grant No.2020B090922002)Guangdong Provincial Basic and Applied Basic Research Fund Project of China(Grant Nos.2019B1515120094,2022B1515020064)National Natural and Science Foundation of China(Grant No.51775196).
文摘Additive manufacturing of Al-Mg-Sc-Zr alloys is a promising technique for the fabrication of lightweight components with complex shapes.In this study,the effect of the process parameters of selective laser melting(SLM)on the surface morphology,relative density,microstructure,and mechanical properties of Al-Mg-Sc-Zr high-strength aluminum alloys with low Sc content was systematically investigated.The results show that the energy density has an important effect on the surface quality and densification behavior of the Al-Mg-Sc-Zr alloy during the SLM process.As the energy density increased,the surface quality and the number of internal pores increased.However,the area of the fine-grained region at the boundary of the molten pool gradually decreased.When the laser energy density was set to 151.52 J/mm3,a low-defect sample with a relative density of 99.2%was obtained.After heat treatment,the area of the fine grains at the boundary increased significantly,thereby contributing to the excellent mechanical properties.The microstructure was characterized by a unique“fan-shaped”heterogeneous structure.As the energy density increased,the microhardness first increased and then decreased,reaching a maximum value of 122 HV0.3.With the optimized process parameters,the yield strength(YS),ultimate tensile strength(UTS),and elongation of the as-built Al-Mg-Sc-Zr alloys were 346.8±3.0 MPa,451.1±5.2 MPa,14.6%±0.8%,respectively.After heat treatment at 325°C for 8 h,the hardness increased by 38.5%to 169 HV0.3,and the YS and UTS increased by 41.3%and 18.1%,respectively,to 490.0±9.0 MPa and 532.7±7.8 MPa,respectively,while the elongation slightly decreased to 13.1%±0.7%.
基金Guangdong Provincial Basic and Applied Basic Research Foundation of China(Grant Nos.2019B1515120094,2022B1515020064)National Natural Science Foundation of China(Grant No.52073105)Guangdong Provincial Key Field Research and Development Program of China(Grant No.2020B090922002).
文摘Laser powder bed fusion(LPBF)is an innovative method for manufacturing multimaterial components with high geometrical resolution.The LPBF-printing sequences of materials may be diverse in the actual design and application of multimaterial components.In this study,multimaterial copper(CuSn10)–steel(316 L)structures are printed using different building strategies(printing 316 L on CuSn10 and printing CuSn10 on 316 L)via LPBF,and the characteristics of two interfaces(the 316 L/CuSn10 or“L/C”and CuSn10/316 L or“C/L”interfaces)are investigated.Subsequently,the interfacial melting mode and formation mechanisms are discussed.At the L/C interface,the keyhole melting mode induced by the high volumetric energy density(EL/C=319.4 J/mm3)results in a large penetration depth in the pre-solidified layer and enhances laser energy absorption,thus promoting the extensive migration of materials and intense intermixing of elements to form a wide diffusion zone(∼400μm).At the C/L interface,the conduction mode induced by the low volumetric energy density(EC/L=74.1 J/mm3)results in a narrow diffusion zone(∼160μm).The interfacial defects observed are primarily cracks and pores.More cracks appeared at the C/L interface,which is attributable to the weak bonding strength of the narrow diffusion zone.This study provides guidance and reference for the design and manufacturing of multimaterial components via LPBF using different building strategies.
