Effects of Al- Si addition on hot modulus of rup- ture ~ HMOR） . thermal shock resistance ~ TSR~ . phase composition and mierostructure of low-carbon MgO - C materials were investigated. The results show that： Al an...Effects of Al- Si addition on hot modulus of rup- ture ~ HMOR） . thermal shock resistance ~ TSR~ . phase composition and mierostructure of low-carbon MgO - C materials were investigated. The results show that： Al and Si addition to low-carbon MgO - C materials leads to dramatic increase in MOR at elevated temperatures; it increases from 4 MPa to 11 -21 MPa at 1 200 ℃ and from 2 MPa to 21 -29 MPa at 1 400 ℃. Al and Si addition to low-carbon MgO - C materials also improves TSR： residual strength ratio after thermal shock when △T = 1 200 ℃ is increased,from 44% to 73% - 77%. Al reacts with C and N2 to form, Al4C3 and AlN, Si reacts with C to form SiC. Ultimately. in-situ formed non- oxides increase appreciably with temperature rising and are well interlaced in periclase skeleton structure at 1 300 -1 400 ℃. which is beneficial to thermomechanical properties.展开更多
To tackle the common issue of green defects in material extrusion(MEX)additive manufacturing(AM)cemented carbides,warm isostatic pressing(WIP)was introduced to eliminate defects of MEX WC-9Co cemented carbide greens,t...To tackle the common issue of green defects in material extrusion(MEX)additive manufacturing(AM)cemented carbides,warm isostatic pressing(WIP)was introduced to eliminate defects of MEX WC-9Co cemented carbide greens,thereby improving both microstructure uniformity and mechanical properties of sintered bodies.The results indicate that WIP reduces defects in MEX greens,thus decreasing the dimensions and numbers of defects,modifying shapes of pores within sintered bodies,while preserving surface quality and shape characteristics.Compared with WC-9Co prepared via MEX followed by debinding and sintering(DS),the hardness of WC-9Co prepared using MEX-WIP-DS does not change significantly,ranging HV_(30)1494-1508,the transverse rupture strength increases by up to 49.3%,reaching 2998-3514 MPa,and the fracture toughness remains high,ranging 14.8-17.0 MPa·m^(1/2).The mechanical properties surpass comparable cemented carbides fabricated through other AM methods and are comparable to those produced by powder metallurgy.The integration of green WIP into MEX-DS broadens the MEX processing window,and improves the overall mechanical properties of MEX AM WC-Co cemented carbides.展开更多
Additive manufacturing(AM)is a widely applied manufacturing paradigm used for the layer-by-layer fabrica-tion of desired components and objects,especially for those with highly intricate geometry.Extrusion-based AM,wh...Additive manufacturing(AM)is a widely applied manufacturing paradigm used for the layer-by-layer fabrica-tion of desired components and objects,especially for those with highly intricate geometry.Extrusion-based AM,which is a subcategory of AM processing technologies,is characterized by the facilitation of controlled and successive deposition of feedstock AM materials through the nozzles of printer heads onto a print bed.Extrusion-based AM processing enables design freedom but offers cost efficiency and process simplicity when compared to other AM categories i.e.liquid-and powder-based AM technologies.The extrusion-based AM process has become increasingly widespread over the last two decades because of the expanding material options that can be used in this technology,and its capacity to be hybridised through the addition of multiple printheads or incorpora-tion into a secondary manufacturing system.Despite the promising aspects of the extrusion-based AM process,increasing demands for customised extrusion-based printed products and an expanding range of extrusion-based AM materials create both material-and process-related challenges that limit the suitability of extrusion-based AM processes for some specific applications.Consequently,the principal objective of this review paper is to conduct a suitability analysis of extrusion-based AM processes.The suitability analysis follows a review and discussion about the extrusion-based AM process,and an assessment of easy-and hard-to-print extrusion-based AM mate-rials.This paper,therefore,provides a comprehensive suitability analysis of each extrusion-based AM process while also providing some promising ideas for improving their current suitability levels.The findings and ratings reported in this paper importantly offers viewpoints that would support better futuristic comparisons between developed and developing extrusion-based AM processes,especially as businesses look to adopt the right AM solutions.展开更多
Four Zr–Cu–Fe–Al-based bulk metallic glasses（BMGs） with Zr contents greater than 65at% and minor additions of Nb were designed and prepared. The glass forming abilities, thermal stabilities, mechanical properties...Four Zr–Cu–Fe–Al-based bulk metallic glasses（BMGs） with Zr contents greater than 65at% and minor additions of Nb were designed and prepared. The glass forming abilities, thermal stabilities, mechanical properties, and corrosion resistance properties of the prepared BMGs were investigated. These BMGs exhibit moderate glass forming abilities along with superior fracture and yield strengths compared to previously reported Zr–Cu–Fe–Al BMGs. Specifically, the addition of Nb into this quaternary system remarkably increases the plastic strain to 27.5%, which is related to the high Poisson＇s ratio and low Young＇s and shear moduli. The Nb-bearing BMGs also exhibit a lower corrosion current density by about one order of magnitude and a wider passive region than 316 L steel in phosphate buffer solution（PBS, pH 7.4）. The combination of the optimized composition with high deformation ability, low Young＇s modulus, and excellent corrosion resistance properties indicates that this kind of BMG is promising for biomedical applications.展开更多
Overcasting is a new kind of dissimilar joining technique used to produce the aluminum（solid）/magnesium（liquid） bonding bi-metallic material in this study. For the Al/Mg（A390/AM60） bi-metallic samples, the inter...Overcasting is a new kind of dissimilar joining technique used to produce the aluminum（solid）/magnesium（liquid） bonding bi-metallic material in this study. For the Al/Mg（A390/AM60） bi-metallic samples, the interface microstructures are the research points, which directly influence the mechanical properties. It is, therefore, of vital importance to find a method to improve the interface microstructures. This research focused on the effect of the calcium（Ca） addition in the liquid Mg alloys and the heat treatment on the A390/AM60 interface microstructures of the bi-metallic samples. The testing results showed that, with Ca addition in AM60, owing to two possible reasons, the interface microstructure and the shear strength of the A390/AM60 bi-metallic samples could be improved. The heat treatment could further improve the interface microstructure and the mechanical properties by dissolving β-Mg_（17）Al_（12） into α-Mg and destroying the Mg_2Si layer structure.展开更多
The limitations in electronics in arithmetic, algebraic & logic processing are well known. Very high speed performance (above GHz) are not expected at all in conventional electronic mechanism. To achieve high spee...The limitations in electronics in arithmetic, algebraic & logic processing are well known. Very high speed performance (above GHz) are not expected at all in conventional electronic mechanism. To achieve high speed performance we may think on the introduction of optics instead of electronics for information, processing and computing. Non-linear optical material is a successful candidate in this regard to play a major role in the optically controlled switching systems and therefore in all-optical parallel computation these materials can show a very good potential aspect. In this paper, we have proposed a new method of an optical half adder as well as full adder circuit for binary addition using non-linear and linear optical materials.展开更多
The composite material layering process has attracted considerable attention due to its production advantages,including high scalability and compatibility with a wide range of raw materials.However,changes in process ...The composite material layering process has attracted considerable attention due to its production advantages,including high scalability and compatibility with a wide range of raw materials.However,changes in process conditions can lead to degradation in layer quality and non-uniformity,highlighting the need for real-time monitoring to improve overall quality and efficiency.In this study,an AI-based monitoring system was developed to evaluate layer width and assess quality in real time.Three deep learning models Faster Region-based Convolutional Neural Network(R-CNN),You Only Look Once version 8(YOLOv8),and Single Shot MultiBox Detector(SSD)were compared,and YOLOv8 was ultimately selected for its superior speed,flexibility,and scalability.The selected model was integrated into a user-friendly interface.To verify the reliability of the system,bead width control experiments were conducted,which identified feed speed and extrusion speed as the key process parameters.Accordingly,a Central Composite Design(CCD)experimental plan with 13 conditions was applied to evaluate layer width and validate the system’s reliability.Finally,the proposed system was applied to the additive manufacturing of an aerospace component,where it successfully detected bead width deviations during printing and enabled stable fabrication with a maximum geometric deviation of approximately 6 mm.These findings demonstrate the critical role of real-time monitoring of layer width and quality in improving process stability and final product quality in composite material additive manufacturing.展开更多
An investigation was conducted to examine the impact of additive mixing with wheat straw(WS)for pellet making.This study manufactured seven types of pellets with different additive combina-tions to evaluate pellet qua...An investigation was conducted to examine the impact of additive mixing with wheat straw(WS)for pellet making.This study manufactured seven types of pellets with different additive combina-tions to evaluate pellet quality characteristics and their relationships.A laboratory-type hammer mill and a pellet mill were used for feedstock preparation and pellet production.Experimental investigations showed that the lignin content increased from 7.0%to 13.1%,which was a primary need for pelletization.Also,the heating value rose from 17.02 to 20.36 MJ/kg.However,the ash content also increased from 7.09%to 16.2%.Results showed that dimension(length and diame-ter),durability,and tensile strength increased significantly with additives while the fines content decreased.The fines content had an inverse relationship with durability and strength.Wheat straw(60%),together with 10%sawdust(SD),10%corn starch(CS),10%bentonite clay(BC),and 10%biochar(BiC),was optimal with good pellet performance(T7).In addition,both the T5 pellets(70%WS,10%SD,10%BiC,and 10%BC)and the T6 pellets(70%WS,10%SD,10%BiC,and 10%CS)provide suitable quality according to EN plus 2015 standard requirements.The ash content of produced pellet was higher than the recommended value,which suggests that further research onto the alternative additive use for ash reduction is needed.展开更多
文摘Effects of Al- Si addition on hot modulus of rup- ture ~ HMOR） . thermal shock resistance ~ TSR~ . phase composition and mierostructure of low-carbon MgO - C materials were investigated. The results show that： Al and Si addition to low-carbon MgO - C materials leads to dramatic increase in MOR at elevated temperatures; it increases from 4 MPa to 11 -21 MPa at 1 200 ℃ and from 2 MPa to 21 -29 MPa at 1 400 ℃. Al and Si addition to low-carbon MgO - C materials also improves TSR： residual strength ratio after thermal shock when △T = 1 200 ℃ is increased,from 44% to 73% - 77%. Al reacts with C and N2 to form, Al4C3 and AlN, Si reacts with C to form SiC. Ultimately. in-situ formed non- oxides increase appreciably with temperature rising and are well interlaced in periclase skeleton structure at 1 300 -1 400 ℃. which is beneficial to thermomechanical properties.
基金supported by the Key Project of Chinese Academy of Engineering(No.2019-XZ-11)the General Project of Chinese Academy of Engineering(No.2023-XY-18)+1 种基金the Open Fund of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials of China(No.HKDNM201907)the Independent Project of State Key Laboratory of Powder Metallurgy,China。
文摘To tackle the common issue of green defects in material extrusion(MEX)additive manufacturing(AM)cemented carbides,warm isostatic pressing(WIP)was introduced to eliminate defects of MEX WC-9Co cemented carbide greens,thereby improving both microstructure uniformity and mechanical properties of sintered bodies.The results indicate that WIP reduces defects in MEX greens,thus decreasing the dimensions and numbers of defects,modifying shapes of pores within sintered bodies,while preserving surface quality and shape characteristics.Compared with WC-9Co prepared via MEX followed by debinding and sintering(DS),the hardness of WC-9Co prepared using MEX-WIP-DS does not change significantly,ranging HV_(30)1494-1508,the transverse rupture strength increases by up to 49.3%,reaching 2998-3514 MPa,and the fracture toughness remains high,ranging 14.8-17.0 MPa·m^(1/2).The mechanical properties surpass comparable cemented carbides fabricated through other AM methods and are comparable to those produced by powder metallurgy.The integration of green WIP into MEX-DS broadens the MEX processing window,and improves the overall mechanical properties of MEX AM WC-Co cemented carbides.
文摘Additive manufacturing(AM)is a widely applied manufacturing paradigm used for the layer-by-layer fabrica-tion of desired components and objects,especially for those with highly intricate geometry.Extrusion-based AM,which is a subcategory of AM processing technologies,is characterized by the facilitation of controlled and successive deposition of feedstock AM materials through the nozzles of printer heads onto a print bed.Extrusion-based AM processing enables design freedom but offers cost efficiency and process simplicity when compared to other AM categories i.e.liquid-and powder-based AM technologies.The extrusion-based AM process has become increasingly widespread over the last two decades because of the expanding material options that can be used in this technology,and its capacity to be hybridised through the addition of multiple printheads or incorpora-tion into a secondary manufacturing system.Despite the promising aspects of the extrusion-based AM process,increasing demands for customised extrusion-based printed products and an expanding range of extrusion-based AM materials create both material-and process-related challenges that limit the suitability of extrusion-based AM processes for some specific applications.Consequently,the principal objective of this review paper is to conduct a suitability analysis of extrusion-based AM processes.The suitability analysis follows a review and discussion about the extrusion-based AM process,and an assessment of easy-and hard-to-print extrusion-based AM mate-rials.This paper,therefore,provides a comprehensive suitability analysis of each extrusion-based AM process while also providing some promising ideas for improving their current suitability levels.The findings and ratings reported in this paper importantly offers viewpoints that would support better futuristic comparisons between developed and developing extrusion-based AM processes,especially as businesses look to adopt the right AM solutions.
基金financially supported by the National Natural Science Foundation of China (No. 51271018)the Proprietary Program of the State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing (Nos.2011Z-01 and 2012Z-01)
文摘Four Zr–Cu–Fe–Al-based bulk metallic glasses（BMGs） with Zr contents greater than 65at% and minor additions of Nb were designed and prepared. The glass forming abilities, thermal stabilities, mechanical properties, and corrosion resistance properties of the prepared BMGs were investigated. These BMGs exhibit moderate glass forming abilities along with superior fracture and yield strengths compared to previously reported Zr–Cu–Fe–Al BMGs. Specifically, the addition of Nb into this quaternary system remarkably increases the plastic strain to 27.5%, which is related to the high Poisson＇s ratio and low Young＇s and shear moduli. The Nb-bearing BMGs also exhibit a lower corrosion current density by about one order of magnitude and a wider passive region than 316 L steel in phosphate buffer solution（PBS, pH 7.4）. The combination of the optimized composition with high deformation ability, low Young＇s modulus, and excellent corrosion resistance properties indicates that this kind of BMG is promising for biomedical applications.
基金Funded by the National Natural Science Foundation of China(No.51571080)
文摘Overcasting is a new kind of dissimilar joining technique used to produce the aluminum（solid）/magnesium（liquid） bonding bi-metallic material in this study. For the Al/Mg（A390/AM60） bi-metallic samples, the interface microstructures are the research points, which directly influence the mechanical properties. It is, therefore, of vital importance to find a method to improve the interface microstructures. This research focused on the effect of the calcium（Ca） addition in the liquid Mg alloys and the heat treatment on the A390/AM60 interface microstructures of the bi-metallic samples. The testing results showed that, with Ca addition in AM60, owing to two possible reasons, the interface microstructure and the shear strength of the A390/AM60 bi-metallic samples could be improved. The heat treatment could further improve the interface microstructure and the mechanical properties by dissolving β-Mg_（17）Al_（12） into α-Mg and destroying the Mg_2Si layer structure.
文摘The limitations in electronics in arithmetic, algebraic & logic processing are well known. Very high speed performance (above GHz) are not expected at all in conventional electronic mechanism. To achieve high speed performance we may think on the introduction of optics instead of electronics for information, processing and computing. Non-linear optical material is a successful candidate in this regard to play a major role in the optically controlled switching systems and therefore in all-optical parallel computation these materials can show a very good potential aspect. In this paper, we have proposed a new method of an optical half adder as well as full adder circuit for binary addition using non-linear and linear optical materials.
基金support of the Korea Institute of Industrial Technol-ogy as“Development of a remote manufacturing system for high-risk,high-difficulty pipe production processes”(kitech EH-25-0004)supported by the Technology Innovation Program(or Industrial Strategic Technology Development Program)(RS-2023–00237714+2 种基金Development of Dynamic Metrology Tool for CMP Process StabilizationRS-2025–02634755Development of Real-Time Electrical Fire Prevention System Technology Reflecting the Characteristics of Traditional Markets)funded by the Ministry of Trade,Industry&Energy(MOTIE,Republic of Korea).
文摘The composite material layering process has attracted considerable attention due to its production advantages,including high scalability and compatibility with a wide range of raw materials.However,changes in process conditions can lead to degradation in layer quality and non-uniformity,highlighting the need for real-time monitoring to improve overall quality and efficiency.In this study,an AI-based monitoring system was developed to evaluate layer width and assess quality in real time.Three deep learning models Faster Region-based Convolutional Neural Network(R-CNN),You Only Look Once version 8(YOLOv8),and Single Shot MultiBox Detector(SSD)were compared,and YOLOv8 was ultimately selected for its superior speed,flexibility,and scalability.The selected model was integrated into a user-friendly interface.To verify the reliability of the system,bead width control experiments were conducted,which identified feed speed and extrusion speed as the key process parameters.Accordingly,a Central Composite Design(CCD)experimental plan with 13 conditions was applied to evaluate layer width and validate the system’s reliability.Finally,the proposed system was applied to the additive manufacturing of an aerospace component,where it successfully detected bead width deviations during printing and enabled stable fabrication with a maximum geometric deviation of approximately 6 mm.These findings demonstrate the critical role of real-time monitoring of layer width and quality in improving process stability and final product quality in composite material additive manufacturing.
文摘An investigation was conducted to examine the impact of additive mixing with wheat straw(WS)for pellet making.This study manufactured seven types of pellets with different additive combina-tions to evaluate pellet quality characteristics and their relationships.A laboratory-type hammer mill and a pellet mill were used for feedstock preparation and pellet production.Experimental investigations showed that the lignin content increased from 7.0%to 13.1%,which was a primary need for pelletization.Also,the heating value rose from 17.02 to 20.36 MJ/kg.However,the ash content also increased from 7.09%to 16.2%.Results showed that dimension(length and diame-ter),durability,and tensile strength increased significantly with additives while the fines content decreased.The fines content had an inverse relationship with durability and strength.Wheat straw(60%),together with 10%sawdust(SD),10%corn starch(CS),10%bentonite clay(BC),and 10%biochar(BiC),was optimal with good pellet performance(T7).In addition,both the T5 pellets(70%WS,10%SD,10%BiC,and 10%BC)and the T6 pellets(70%WS,10%SD,10%BiC,and 10%CS)provide suitable quality according to EN plus 2015 standard requirements.The ash content of produced pellet was higher than the recommended value,which suggests that further research onto the alternative additive use for ash reduction is needed.
