A novel Mg_(98.5)Zn_(0.5)Y alloy sheet with ultrafine grains and exceptional electromagnetic shielding performance has been fabricated using friction stir processing(FSP).This study investigates the impact of FSP on t...A novel Mg_(98.5)Zn_(0.5)Y alloy sheet with ultrafine grains and exceptional electromagnetic shielding performance has been fabricated using friction stir processing(FSP).This study investigates the impact of FSP on the microstructure,mechanical properties,and electromagnetic interference(EMI)shielding effectiveness(SE)of the alloy,specifically across three distinct layers within the stir zone(SZ):Top,Middle,and Bottom.The results reveal that the Mg_(12)YZn long-period stacking ordered(LPSO)phase is the predominant structure,undergoing significant grain refinement.The grain size is drastically reduced from 1.5 mm in the as-cast state to 12.6μm,10.0μm,and 7.1μm in the Top,Middle,and Bottom,respectively.This grain refinement and fragmentation of the LPSO phase into nanoscale particles result in a substantial enhancement of mechanical properties.The ultimate tensile strength(UTS)reached 358.2 MPa with an elongation(EL)of 15.1%,reflecting a 344% increase in strength and a 733% improvement in ductility compared to the as-cast material.Simultaneously,the EMI SE was maintained between 70 and 110.4 dB over a broad frequency range(30-4500 MHz).Despite the nanoscale LPSO particles contributing minimally to EMI shielding,the lamellar LPSO structure demonstrated excellent performance through multiple electromagnetic wave reflections within the matrix.These findings underscore the dual benefits of FSP in improving both mechanical strength and electromagnetic shielding effectiveness,positioning this Mg_(98.5)Zn_(0.5)Y alloy for advanced applications in the electronics and telecommunications sectors.展开更多
To investigate the possibility of substituting the mechanical stirring system with electromagnetic stirring (EMS) system for aluminum rheo die-casting, the EMS under the different stirring cooling conditions was carri...To investigate the possibility of substituting the mechanical stirring system with electromagnetic stirring (EMS) system for aluminum rheo die-casting, the EMS under the different stirring cooling conditions was carried out. It was found that in the early period of solidification, the dendrite breakages led to a fine primary phase. When dendrites grew coarsely, the effect of ripening on grain size overwhelmed that of dendrite breakage. It was also found that the high cooling rate favored large nucleation rate, and led to a fine primary phase. But high cooling rate also made the growth rate of the dendrite arm, which prevented the dendrite arm from being sheared off. Therefore there were a suitable stirring time and suitable cooling rate to obtain the best rheo die-casting structure. Qualified semisolid A356 aluminum alloy was successfully manufactured with short time EMS.展开更多
A wide range of industrial metallurgical heating and melting processes are carried out using electrothermal and electromagnetic technologies.The application of electromagnetic processing offers many advantages from te...A wide range of industrial metallurgical heating and melting processes are carried out using electrothermal and electromagnetic technologies.The application of electromagnetic processing offers many advantages from technological, ecological and economical point of view.Although the technology level of the electromagnetic heating and melting installations and processes used in the industry today is very high,there are still potentials for improvement and optimization.In this paper recent applications and future development trends for efficient use of electromagnetic processing technologies in metallurgical and non-metallic material processes are described along selected examples in the field of heating for melting,forging,joining and solidification.展开更多
The hypereutectic Al-Si alloy was fabricated by hot extrusion process after solidified under electromagnetic stirring,and the microstructure and mechanical properties of the alloy were studied.The results show that th...The hypereutectic Al-Si alloy was fabricated by hot extrusion process after solidified under electromagnetic stirring,and the microstructure and mechanical properties of the alloy were studied.The results show that the ultimate tensile strength and elongation of the alloy reached 229.5 MPa and 4.6%,respectively with the extrusion ratio of 10,and 263.2 MPa and 5.4%,respectively with extrusion ratio of 20.This indicates that the mechanical properties of the alloy are obviously improved with the increase of extrusion ratio.After hot extruded,the primary Si,eutectic Si,Mg2Si,AlNi,Al7Cu4Ni and Al-Si-Mn-Fe-Cr-Mo phases are refined to different extent,and the efficiency of refinement is obvious more and more with the increase of extrusion ratio.After T6 heat treatment,the sharp corners of these phases become passivated and roundish,and the mechanical properties are improved.The ultimate tensile strength of the extruded alloy after T6 heat treatment reaches 335.3 MPa with extrusion ratio of 10 and 353.6 MPa with extrusion ratio of 20.展开更多
基金supported by Yunnan Major Scientific and Technological Projects(Grant No 202202AG050011)the Sichuan Science and Technology Program(No.2023YFG0218)+2 种基金Guizhou Provincial Department of Education Open Recruitment and Leadership Scientific and Technological Attack Project(Guizhou Education Technology[2024]No 003)Anshu University 2024 Annual School-Level Scientific Research Project(asxybsjj202413)Guizhou Provincial Basic Research Program(Natural Science)(No.QKHJC[2024]Youth 214).
文摘A novel Mg_(98.5)Zn_(0.5)Y alloy sheet with ultrafine grains and exceptional electromagnetic shielding performance has been fabricated using friction stir processing(FSP).This study investigates the impact of FSP on the microstructure,mechanical properties,and electromagnetic interference(EMI)shielding effectiveness(SE)of the alloy,specifically across three distinct layers within the stir zone(SZ):Top,Middle,and Bottom.The results reveal that the Mg_(12)YZn long-period stacking ordered(LPSO)phase is the predominant structure,undergoing significant grain refinement.The grain size is drastically reduced from 1.5 mm in the as-cast state to 12.6μm,10.0μm,and 7.1μm in the Top,Middle,and Bottom,respectively.This grain refinement and fragmentation of the LPSO phase into nanoscale particles result in a substantial enhancement of mechanical properties.The ultimate tensile strength(UTS)reached 358.2 MPa with an elongation(EL)of 15.1%,reflecting a 344% increase in strength and a 733% improvement in ductility compared to the as-cast material.Simultaneously,the EMI SE was maintained between 70 and 110.4 dB over a broad frequency range(30-4500 MHz).Despite the nanoscale LPSO particles contributing minimally to EMI shielding,the lamellar LPSO structure demonstrated excellent performance through multiple electromagnetic wave reflections within the matrix.These findings underscore the dual benefits of FSP in improving both mechanical strength and electromagnetic shielding effectiveness,positioning this Mg_(98.5)Zn_(0.5)Y alloy for advanced applications in the electronics and telecommunications sectors.
文摘To investigate the possibility of substituting the mechanical stirring system with electromagnetic stirring (EMS) system for aluminum rheo die-casting, the EMS under the different stirring cooling conditions was carried out. It was found that in the early period of solidification, the dendrite breakages led to a fine primary phase. When dendrites grew coarsely, the effect of ripening on grain size overwhelmed that of dendrite breakage. It was also found that the high cooling rate favored large nucleation rate, and led to a fine primary phase. But high cooling rate also made the growth rate of the dendrite arm, which prevented the dendrite arm from being sheared off. Therefore there were a suitable stirring time and suitable cooling rate to obtain the best rheo die-casting structure. Qualified semisolid A356 aluminum alloy was successfully manufactured with short time EMS.
文摘A wide range of industrial metallurgical heating and melting processes are carried out using electrothermal and electromagnetic technologies.The application of electromagnetic processing offers many advantages from technological, ecological and economical point of view.Although the technology level of the electromagnetic heating and melting installations and processes used in the industry today is very high,there are still potentials for improvement and optimization.In this paper recent applications and future development trends for efficient use of electromagnetic processing technologies in metallurgical and non-metallic material processes are described along selected examples in the field of heating for melting,forging,joining and solidification.
基金supported by National Natural Science Foundation of China (Grant No. 50971092)Innovation Team Plan pf Liaoning Provincical Education Department (Grant no. 2007T132)
文摘The hypereutectic Al-Si alloy was fabricated by hot extrusion process after solidified under electromagnetic stirring,and the microstructure and mechanical properties of the alloy were studied.The results show that the ultimate tensile strength and elongation of the alloy reached 229.5 MPa and 4.6%,respectively with the extrusion ratio of 10,and 263.2 MPa and 5.4%,respectively with extrusion ratio of 20.This indicates that the mechanical properties of the alloy are obviously improved with the increase of extrusion ratio.After hot extruded,the primary Si,eutectic Si,Mg2Si,AlNi,Al7Cu4Ni and Al-Si-Mn-Fe-Cr-Mo phases are refined to different extent,and the efficiency of refinement is obvious more and more with the increase of extrusion ratio.After T6 heat treatment,the sharp corners of these phases become passivated and roundish,and the mechanical properties are improved.The ultimate tensile strength of the extruded alloy after T6 heat treatment reaches 335.3 MPa with extrusion ratio of 10 and 353.6 MPa with extrusion ratio of 20.
