检索结果-南通市图书馆

Rare Metals 2024年第5期43卷 2275-2281页

作者： Guo-Chao Li Xu Cheng Hua-Ming Wang national engineering laboratory of additive manufacturing for large metallic components and engineering research center of Ministry of education on laser direct manufacturing for large metallic components School of Materials Science and EngineeringBeihang UniversityBeijing 100191China

The solid solution and aging treatment for conventional manufacturing processes might not be suitable for laser additive manufactured titanium alloys due to the different lamellar *** this study,the influence of aging temperatures(600,700 and 800°C)on microstructure and mechanical properties of titanium alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si was *** results indicate that after solid solution treatment at 970°C followed by water quenching,the alloy mainly consists of coarsening lamellar a phase in martensite α' *** at 600°C will not change the size of primary lamellar α phase but lead to huge amount of secondary a phases(α_(s))generating with very fine *** increasing the aging temperature,the number of α_(s) decreases but with coarsened *** aged at 800°C,the width of the asphase reaches 350 nm,almost 7 times wider than that aged at 600°*** changing size of α_(s) obviously influences the property of the *** fine α_(s) leads to high strength and microhardness but low plasticity,and specimen aged at 700°C with suitable assize has the best comprehensive properties.

关键词： α+βtitanium alloy laser additive manufacturing Solid solution and aging treatment Microstructure Room temperature tensile property

additive manufacturing of magnesium matrix composites: Comprehensive review of recent progress and research perspectives

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2023年第2期11卷 425-461页

作者： Chenghang Zhang Zhuo Li Jikui Zhang Haibo Tang Huaming Wang Ningbo Institute of Technology Beihang UniversityNingbo315800China national engineering laboratory of additive manufacturing for large metallic components Beihang University37 Xueyuan RoadBeijingChina research Institute for Frontier Science Beihang University37 Xueyuan RoadBeijingChina research center on laser direct manufacturing for large Critical metallic Component Beihang University37 Xueyuan RoadBeijingChina

The magnesium matrix composites(MMCs) formed by introducing reinforcements to magnesium alloys overcome the limitations of the mechanical properties to a certain extent, presenting unique and excellent properties that any component does not have, such as high specific stiffness and specific strength, good dimensional stability, outstanding shock absorption performance, excellent electromagnetic shielding and hydrogen storage characteristics, etc. As an emerging manufacturing technology, additive manufacturing(AM) is based on the design of threedimensional(3D) data model to obtain 3D objects through layer-by-layer processing, which possesses the advantages of short manufacturing cycle, high material utilization rate, high degree of design freedom, excellent mechanical properties and the ability to fabricate complex structural components. Combining the high stiffness and high strength properties of MMCs and the technical advantages of AM forming complex structural parts with high performance, the prepared AM MMCs have huge potential advantages and broad application prospects in new high-tech industries such as automobile, aerospace, consumer electronics and biomedicine, etc. This paper reviews the research progress in the field of AM MMCs, mainly introduces the main AM technologies, including selective laser melting(SLM), electron beam selective melting(EBSM), laser engineered net shaping(LENS) and wire and arc additive manufacturing(WAAM). The formation mechanism and control methods of the typical defects including balling effect, porosity, poor fusion, loss of alloy elements and cracks produced during AM are discussed. The main challenges of AM MMCs are proposed from the aspects of composition design and the preparation of powder raw material. The relationship between the microstructure and mechanical properties, corrosion performance and biocompatibility of AM MMCs are elaborated in detail. The application potential of AM MMCs in various fields at present and in th

关键词： Magnesium matrix composites additive manufacturing Defects Microstructure Properties

Effects of annealing temperature and cooling rate on microstructures of a novel titanium alloy Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si manufactured by laser additive manufacturing

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel research(International) 2018年第4期25卷 442-452页

作者： Guo-chao Li Xu Cheng Xiang-jun Tian national engineering laboratory of additive manufacturing for large metallic components and engineering research center of Ministry of education on laser direct manufacturing for large metallic components School of Materials Science and Engineering Beihang University Beijing 100091 China

The microstructure changes of Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si alloy manufactured by laser additive manufacturing （LAM） are systematically investigated with statistical analysis of primary α phase （αp） and secondary α phase （αs） under different annealing conditions. Results indicate that, with the increase in holding temperature, the content of αp lamellas decreases with the increasing αs content, maintaining the total α phases concentration stabilized. The width of αp lamellas and the nominal specific surface area of α phase both exhibit positive correlation with the temperature, while the increment of αp and the widths of αs lamellas show an increase-decrease tendency. Besides, with the decrease in cooling rate, the total content of α and the width of αp lamellas increase, while the nominal specific surface area of α phase shows no significant change. The results indicate that, in the annealing process, the holding temperature determines the surplus and growth interfaces of % lamellas, and the cooling rate influences the nucleation quantity of c^s in unit time. During the cooling stage, the αp lamellas grow initially, and then, the nucleation and crab-like structure growth occur followed by those of the αs lamellas. The time intervals among them are influenced by cooling rate. The mechanism of microstructure formation of the LAMed titanium alloy during annealing stage was discussed, which would guide for the heat treatment method to achieve required microstructure.

关键词： Novel titanium alloy Annealing Microstructure statistics Holding temperature Cooling rate

Alloy design for laser powder bed fusion additive manufacturing:a critical review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Extreme manufacturing 2024年第2期6卷 29-63页

作者： Zhuangzhuang Liu Qihang Zhou Xiaokang Liang Xiebin Wang Guichuan Li Kim Vanmeensel Jianxin Xie Key laboratory for Advanced Materials Processing(MOE) Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083People’s Republic of China Beijing Advanced Innovation center for Materials Genome engineering University of Science and Technology BeijingBeijing 100083People’s Republic of China Beijing laboratory of metallic Materials and Processing for Modern Transportation Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083People’s Republic of China Capital Aerospace Machinery Corporation Limited Beijing 100076People’s Republic of China Key laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of education) Shandong UniversityJingshi Road 17923Jinan 250061People’s Republic of China Department of Materials engineering KU LeuvenLeuven 3001Belgium

Metal additive manufacturing(AM)has been extensively studied in recent *** the significant progress achieved in manufacturing complex shapes and structures,challenges such as severe cracking when using existing alloys for laser powder bed fusion(L-PBF)AM have *** challenges arise because commercial alloys are primarily designed for conventional casting or forging processes,overlooking the fast cooling rates,steep temperature gradients and multiple thermal cycles of *** address this,there is an urgent need to develop novel alloys specifically tailored for L-PBF *** review provides a comprehensive summary of the strategies employed in alloy design for *** aims to guide future research on designing novel alloys dedicated to L-PBF instead of adapting existing *** review begins by discussing the features of the L-PBF processes,focusing on rapid solidification and intrinsic heat ***,the printability of the four main existing alloys(Fe-,Ni-,Al-and Ti-based alloys)is critically assessed,with a comparison of their conventional *** was found that the weldability criteria are not always applicable in estimating ***,the review presents recent advances in alloy development and associated strategies,categorizing them into crack mitigation-oriented,microstructure manipulation-oriented and machine learning-assisted ***,an outlook and suggestions are given to highlight the issues that need to be addressed in future work.

关键词： laser powder bed fusion alloy design printability crack mitigation

Effect of thermal deformation on microstructure and properties of TC18 titanium alloy produced by laser additive manufacturing

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel research(International) 2020年第12期27卷 1476-1484页

作者： Xiao-dong Li Chang-yue Qiu Yu-ting Liu Hong-fang Wang Dong-dong Zheng Yan-yan Zhu Shu-quan Zhang national engineering laboratory of additive manufacturing for large metallic components and engineering researchcenter Beijing 100191China Ministry of education on laser direct manufacturing for large metallic components Beijing 100191China Beijing engineering Technological research center on laser direct manufacturing for large Critical metallic Component Beijing 100191China School of Materials Science and engineering Beihang UniversityBeijing 100191China

Grain boundary of α phase damaged ductility of laser melting-deposited TC18 titanium alloy and grain boundary of α phases were difficult to break by nominal heat treatment. An extra thermal deformation was introduced to break the grain boundary of α phase with the improved mechanical property of TC18 titanium alloy fabricated by laser melting deposition *** indicated that after thermal deformation, β grains in alloy seriously elongated. When sample was deformed at temperatures from 750 to 850 ℃, α phase exhibited both rod and irregular morphologies with discontinuous distribution at grain boundary, and the subsequent heat treatment would lead to spheroidization of the α phase. However, after deformation at 900 ℃, α phase transferred into β phase and the subsequent heat treatment would make continuous grain boundary of α phase reappear. The suitable hot deformation can effectively break the continuous grain boundary in laser melting-deposited TC18 alloy with respected improved ductility.

关键词： laser additive manufacturing Nearβtitanium alloy Thermal deformation Heat treatment Microstructural characteristics

Improvement of proof-ultimate strength difference in laser additive manufactured Ti-6Al-2V-1.5Mo-0.5Zr-0.3Si alloy by tuning basketweave structure

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel research(International) 2019年第6期26卷 631-636页

作者： Guo-chao Li Xu Cheng Hua-ming Wang national engineering laboratory of additive manufacturing for large metallic components and engineering research center of Ministry of education on laser direct manufacturing for large metallic components School of Materials Science and Engineering Beihang University Beijing 100191 China Beijing Yuding additive manufacturing research Institute Co. Ltd. Beijing 102206 China

After annealed at 1000 ℃, a special basket-weave structure is obtained in laser additive manufactured Ti-6Al-2V-1.5Mo- 0.5Zr-0.3Si alloy. The unit of the special basket-weave structure is a lamellas clusters, which consist of lamellar primary ot (otp), crab-like structures at the edges of otp and lamellar secondary a (as) on both sides of otp. As the units of basket-weave structures, the width of the clusters is much larger than that of a lamellas in as-deposited alloy. The formation temperature and process of the special basket-weave structure are studied, and the room temperature properties are tested and compared with the as-deposited alloy. The results show that the formation of the special basket-weave structure finishes within about 30 s and crab-like structures form earlier than lamellar as. The yield strength of the alloy is decreased by about 75 MPa compared to that of the as-deposited alloy. Besides, the proof-ultimate strength difference of the alloy is two times higher than that of the as-deposited alloy with about 34% improvement for the impact toughness. It is because ot colony size shows a positive correlation to the width of the unit forming basket-weave structure. The enhancement in proof-ultimate strengthdifference could significantly improve the toughness of the alloy, and thus effectively increase the safety of the alloy.

关键词： Titanium alloy Basket-weave structure Formation process a colony size Yield strength

Mechanical properties and microstructure of 3D-printed high Co–Ni secondary hardening steel fabricated by laser melting deposition

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2017年第9期24卷 1027-1033页

作者： Hui-ping Duan Xiao Liu Xian-zhe Ran Jia Li Dong Liu School of Materials Science and engineering Beihang UniversityBeijing 100191China national engineering laboratory of additive manufacturing for large metallic components Beijing 100191China engineering research center of Ministry of education on laser direct manufacturing for large metallic Component Beijing 100191China

The mechanical properties and microstructure of the 3D-printed high Co–Ni secondary hardening steel fabricated by the laser melting deposition technique was investigated using a material testing machine and electron microscopy. A microstructure investigation revealed that the samples consist of martensite laths, fine dispersed precipitates, and reverted austenite films at the martensite lath boundaries. The precipitates are enriched with Co and Mo. Because the sample tempered at 486°C has smaller precipitates and a higher number of precipitates per unit area, it exhibits better mechanical properties than the sample tempered at 498°C. Although the 3D-printed samples have the same phase constituents as Aer Met 100 steel, the mechanical properties are slightly worse than those of the commercial wrought Aer Met 100 steel because of the presence of voids.

关键词： laser deposition high strength steel mechanical properties microstructure

Microstructure and properties of hybrid additive manufacturing 316L component by directed energy deposition and laser remelting

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel research(International) 2020年第7期27卷 842-848页

作者： Xiao-hui Chen Bo Chen Xu Cheng Guo-chao Li Zheng Huang national engineering laboratory of additive manufacturing for large metallic Components and Engineering Research CenterMinistry of Education on Laser Direct Manufacturing for Large Metallic ComponentsSchool of Materials Science and EngineeringBeihang UniversityBeijing 100191China research center for Processing AECC Shanghai Commercial Aircraft Engine Manufacturing Co.Ltd.Shanghai 201306China

Arc additive manufacturing is a high-productivity and low-cost technology for directly fabricating fully dense metallic ***,this technology with high deposit rate would cause degradation of dimensional accuracy and surface quality of the metallic component.A novel hybrid additive manufacturing technology by combining the benefit of directed energy deposition and laser remelting is *** hybrid technology is successfully utilized to fabricate 316L component with excellent surface *** show that laser remelting can largely increase the amount ofδphases and eliminateσphases in additive manufacturing 316L component surface due to the rapid *** leads to the formation of remelting layer with higher microhardness and excellent corrosion resistance when compared to the steel made by directed energy deposition *** laser remelting power can improve surface quality as well as corrosion resistance,but degrade microhardness of remelting layer owing to the decrease inδphases.

关键词： Hybrid additive manufacturing laser remelting directed energy deposition Microstructure Corrosion resistance

Microstructural development and wear properties analyses of Fe-based coatings on bainitic steel by laser cladding

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel research(International) 2022年第4期29卷 687-697页

作者： Run-feng Peng Min Zhang Yu-hang Li Yue-long Yu Ying-chun Guan Zhun-li Tan School of Mechanical Electronic and Control EngineeringMaterials Science&Engineering Research CenterBeijing Jiaotong UniversityBeijing 100044China School of Mechanical engineering and Automation Beihang UniversityBeijing 100191China national engineering laboratory of additive manufacturing for large metallic components Beihang UniversityBeijing 100083China Hefei Innovation research Institute of Beihang University Hefei 230013AnhuiChina

Wear-resistant Fe-based coating was prepared by high-speed laser cladding on bainitic *** influence of laser scanning speed on microstructure,microhardness,and wear resistance of cladding coating was *** electron microscopy results showed that the coating was mainly composed of dendrite and *** electron microscope images were converted by binary algorithm to facilitate statistics of dendrite and interdendrite *** results indicate that by accelerating the scanning speed,the interdendrite eutectic structure *** to energydispersive X-ray spectroscopy and X-ray diffraction results,the interdendrite was enriched with elements Cr,Mo,and B,and main structures in the coating wereα-Fe,γ-Fe,and M(23)C_(6).The hardness of the coating was much higher than that of the *** diffused from coating to substrate,resulting in a transition zone of ***,with an increase in the scanning speed,the diffusion of elements at the coating–matrix interface decreased,while the hardness and wear resistance of the coating *** refinement and interdendrite(γ-Fe,M_(23)C_(6))increasing due to high scanning speed were the major contributors to the increase in hardness and wear resistance.

关键词： laser cladding Microstructure Wear property Fe-based coating Bainitic steel

Solid-state phase transformation of TC11 titanium during unstable thermal cycling in laser melting deposition process

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel research(International) 2019年第7期26卷 743-750页

作者： Xiao-dong Li Jin Liu Yan-yan Zhu Xu Cheng Dong Liu Ji-kui Zhang national engineering laboratory of additive manufacturing for large metallic components and engineering research center of Ministry of education on laser direct manufacturing for large metallic components School of Materials Science and Engineering Beihang University Beijing 100191 China Beijing Yuding additive manufacturing research Institute Co. Ltd. Beijing 100096 China School of Aircraft Design Beihang University Beijing 100191 China

Thermal cycling procedure during laser additive manufacturing (LAM) process causes the appearance of bright and dark patterns on the etched surface of TC11 alloy components. The formation mechanisms of these patterns and the solid-state transformation related to LAM process are systematically investigated with the predication of temperature fields using the finite element software ABAQUS. The results indicate that by increasing subsequent thermal cycles, the peak temperatures for every cycle decrease. When peak temperatures are above Tβ(phase transition temperature of β phase), which is 1010℃ in TC11 alloy, no pattern is observed. Meanwhile, a decrease in peak temperature leads to appearance of an ultrafine basket-weave α+β microstructure (dark contrast) with gradually increased amount of α colonies in the alloy. A special bimodal microstructure with ‘fork-like'α lamella appears in the layer when the peak temperatures of thermal cycles firstly fall into α+β dual-phase region. And this special bimodal microstructure gives a bright contrast and only appears at the region where the peak temperatures are below 970℃, leaving the rest region with a dark contrast. With the continuous increase in thermal cycles in α+β dual-phase region,α lamella gradually coarsens. After five thermal cycles in α+β two-phase region, no further changes in microstructure are observed, and the morphologies of α lamella in dark and bright regions are almost the same but with different amounts of α phase.

关键词： Thermal cycling laser melting deposition TC11 Solid-state phase transformation Temperature field