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additive manufacturing of NiTi lightweight porous structures bio-mimicking coral skeleton with enhanced mechanical properties and shape memory functions

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Science China(Technological Sciences) 2024年第8期67卷 2461-2474页

作者： LIU Xin GU DongDong YUAN LuHao ZHANG Han SUN JianFeng CHEN WenXin WANG Jie SHI keyu Jiangsu Provincial Research Center for Laser additive manufacturing of high-performance Components College of Materials Science and TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China

Concerning the high demand for lightweight and multifunctional properties of engineering structures, the coral skeleton-inspired sheet-based(CSS) structure, which was a novel bio-mimicking coral skeleton wall-septa architecture with a unique ability to resist wave shocks was fabricated using NiTi alloy by laser powder bed fusion(LPBF) technology. The effects of laser energy density(LED) on surface morphologies, microstructures, phase transformation behavior, and mechanical properties of LPBFfabricated CSS structures were systematically investigated. The results indicated that the size deviation was predominantly governed by powder adhesion and step effect. NiTi CSS structures with LED of 71 J·mm~(-3)possessed superior compressive modulus(~400 MPa), ultimate strength(~13 MPa), and energy absorption efficiency(~69%). The compression fracture mechanism of the LPBF-fabricated NiTi CSS structures was revealed to be predominantly brittle fracture accompanied by ductile fracture. Furthermore, the Ni_4Ti_3 nanoprecipitates induced the precipitation strengthening effect, enabling better shape memory response at LED of 71 J·mm~(-3), with a recoverable strain of 3.63% and recovery ratio of 90.8%, after heating under a pre-strain of 4%. This study highlights the importance of a bionic design strategy for enhancing the mechanical properties of NiTi components and offers the possibility to tailor its functional properties.

关键词： bioinspired structures laser powder bed fusion NiTi shape memory alloy mechanical performance

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Enhanced high-temperature mechanical properties of laser-arc hybrid additive manufacturing of Al-Zn-Mg-Cu alloy via microstructure control

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Journal of materials Science & Technology 2024年第2期169卷 220-234页

作者： Dehua Liu Dongjiang Wu Yunsong Wang Zhuo Chen Changrong Ge Qingyu Zhao Fangyong Niu Guangyi Ma State key laboratory of high-performance Precision manufacturing Dalian University of TechnologyDalian 116024China

Recently,rapid and cost-effective additive manufacturing solutions for lightweight aluminum alloys with excellent high-temperature mechanical properties have been increasingly in *** this study,we combined laser-arc hybrid additive manufacturing with solution and artificial aging treatments to achieve Al-Zn-Mg-Cu alloy with favorable high-temperature strength via microstructure *** pores became the major defect in the as-deposited and heat-treated *** continuous distribution of eutectics with hard-brittle characteristics at the grain boundaries was destructed following heat ***-densityηprecipitates were uniformly dispersed in the heat-treated Al-Zn-Mg-Cu alloy,whereas appeared coarsened and dissolved at 473 K,owing to the rapid diffusion of Zn and *** average 0.2%yield strength(318±16 MPa)and ultimate tensile strength(362±20 MPa)at 473 K af-ter heat treatment were enhanced by approximately 58%and 51%,respectively,compared to those of the as-deposited *** addition,theηprecipitates contributed to lattice distortions and strain fields,which prevented dislocation motion and increased slip deformation resistance at high *** as-deposited specimen exhibited intergranular fracture at 473 K,with cracks preferring to propagate along the aggregated ***,crack propagation proceeded in the sections with more pores in the heat-treated *** approach may provide a valid option for achieving alu-minum alloys with excellent high-temperature mechanical properties.

关键词： Laser-arc hybrid additive manufacturing Al-Zn-Mg-Cu alloy high-temperature strength Heat treatment,Microstructure evolution

Effects of heat treatment on microstructures and properties of a heterostructured alloy with dissimilar components fabricated by WAAM

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Rare Metals 2024年第9期43卷 4441-4461页

作者： Ming-Cai Pan Jun-Qiang Xu Yong Peng Ning-Ning Liang Si Lan Qi Zhou Ke-Hong Wang School of materials Science and Engineering Nanjing University of Science and Technology key laboratory of Controlled Arc Intelligent additive manufacturing Technology

Heat treatment significantly influences homogeneous material microstructures and mechanical properties, which can be improved by an optimal heat treatment process. However, heat treatment application to heterogeneous materials presents significant challenges due to compositional and microstructural heterogeneities. Herein,a laminated heterostructured alloy comprising alternating316L stainless steel（SS） and 18Ni300 maraging steel（MS）layers fabricated using wire and arc additive manufacturing was investigated. A solution treatment was applied at900 °C for 0.5 h. Subsequently, the solution-treated and asfabricated（AF） samples were aged at 500 °C for 4 h; these samples were denoted SA and AT, respectively. The AT phase compositions and orientations were similar to those of AF. The SA 316L SS layer resembled that of AF, but the SA 18Ni300 MS layers exhibited a reduced austenite phase fraction and refined grain size, attributable to solid-state transformation. In the AT sample, aging induced the formation of nanoscale acicular ω phase and ellipsoidal Ni3Ti,Fe2Mo, and X precipitates in the 18Ni300 MS ***, the SA precipitates contained acicular Fe Ni2and ellipsoidal ω, Ni3Ti, and X precipitates, and their fractions were lower than those in AT precipitates. The18Ni300 MS layer microhardness in the heat-treated samples increased due to nanoprecipitation, but the 316L SS layer microhardness resembled that of AF. The AT and SA ultimate tensile strengths increased to（1360 ± 50） and（1473 ± 41） MPa, respectively, attributable to precipitation strengthening. The SA 316L SS layer exhibited a high stress-induced martensite fraction, enhancing the ductility of heated samples.

关键词： Heat treatment Laminated heterostructured alloy Mechanical property Microstructure Wire and arc additive manufacturing

Effect of TiB_(2)Addition on Microstructure and Mechanical Properties of AA8009 Alloy Fabricated by Laser additive manufacturing

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Acta Metallurgica Sinica(English Letters) 2024年第1期37卷 67-77页

作者： Xinxing Xiong Sijie Yu Pei Wang Junfang Qi Haichao Li Xulei Wang Michael Ryan Debajyoti Bhaduri Rossitza Setchi additive manufacturing Institute Shenzhen UniversityShenzhen518060China Henan key laboratory of high performance Carbon Fiber Reinforced Composites Institute of Carbon Matrix CompositesHenan Academy of SciencesZhengzhou450046China School of materials Science and Engineering Shanghai University of Engineering ScienceShanghai201620China School of materials Science and Engineering Zhengzhou University of AeronauticsZhengzhou450046China high-Value manufacturing Research Group School of EngineeringCardiff UniversityCardiffCF243AAUK

The research involves the addition of 5 vol.%TiB_(2)particles into AA8009 alloy powder to synthesize TiB_(2)/AA8009 composite parts produced via laser powder bed fusion(LPBF).The addition of the TiB_(2)particles causes the TiB_(2)/AA8009 composites with and without annealing have lower compressive strength than AA8009 alloy due to the change of the strengthening *** results further indicated that solid solution strengthening was the main strengthening mechanism of the LPBF AA8009 alloy at room temperature whereas Orowan strengthening became the primary strengthening factor after annealing at 673 *** contrast,Orowan strengthening always remained the main strengthening mechanism for the TiB_(2)/AA8009 composite,irrespective of the annealing *** addition,after annealing of the LPBF parts at 673 K,the compressive yield strength(CYS)of the unblended AA8009 alloy specimens had a~2.5 times greater reduction(from 705±16 to 459±30 MPa)compared to that of the composite TiB_(2)/AA8009 samples(from 466±23 to 368±3 MPa).Therefore,TiB_(2)particles can suppress the drop in yield strength of LPBF AA8009 alloy below 673 K,providing a theoretical and experimental basis for the applications of both LPBF AA8009 and TiB_(2)/AA8009 alloys at low and medium temperatures.

关键词： Laser powder bed fusion AA8009 alloy Microstructure Mechanical properties

Absence of ultrasonic-vibration-induced plasticity in metallic glacial glasses

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Rare Metals 2024年第7期43卷 3422-3429页

作者： Zhe Chen Shuai Ren Jian Zhu Jie Shen Xin Li He-Ting Zhang Hong-Ji Lin Sajad Sohrabi Wen-Qing Ruan Zhen-Xuan Zhang Xiong Liang Jiang Ma Jun Shen shenzhen key laboratory of high performance Nontraditional manufacturing College of Mechatronics and Control EngineeringShenzhen UniversityShenzhen 518060China Institute of Physics Chinese Academy of SciencesBeijing 100190China School of Mechanical Electrical and Information EngineeringShandong UniversityWeihai 264209China

Metallic glasses (MGs) have been found to exhibit unexpected ultrasonic-vibration-induced plasticity (UVIP),which provides a promising way to realize room temperature processing and molding of ***,whether all MGs poss... 详细信息

关键词： glasses metallic plasticity

Improving fatigue properties of normal direction ultrasonic vibration assisted face grinding Inconel 718 by regulating machined surface integrity

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International Journal of Extreme manufacturing 2024年第3期6卷 458-475页

作者： Nianwei Xu Renke Kang Bi Zhang Yuan Zhang Chenxu Wang Yan Bao Zhigang Dong State key laboratory of high-performance Precision manufacturing Dalian University of TechnologyDalian 116024People’s Republic of China Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen 518055People’s Republic of China

Fatigue properties are crucial for critical aero-engine components in extreme serviceenvironments,which are significantly affected by surface integrity(SI)indexes(especially surface topography,residual stressσ_(res),and microhardness)after machining ***-direction ultrasonic vibration-assisted face grinding(ND-UVAFG)has advantages in improving the machinability of Inconel 718,but there is a competitive relationship between higher compressiveσ_(res)and higher surface roughness R_(a)in affecting fatigue *** lack of a quantitative relationship between multiple SI indexes and fatigue strength makes theindeterminacy of a regulatory strategy for improving fatigue *** this work,a model of fatigue strength(σ_f)_(sur)considering multiple SI indexes was ***,high-cycle fatigue tests were carried out on Inconel 718 samples with different SI characteristics,and the influence of ND-UVAFG process parameters on SI was *** on SI indexes data,the(σ_f)_(sur)distribution in the grinding surface layer for ND-UVAFG Inconel 718 samples was determined using the developed model,and then the fatigue crack initiation(FCI)sites were *** predicted FCI sites corresponded well with the experimental results,therebyverifying this model.A strategy for improving the fatigue life was proposed in this work,which was to transfer the fatigue source from the machined surface to the bulk material by controlling the SI ***,a critical condition of SI indexes that FCI sites appeared on the surface or in bulk material was given by fitting the predicted *** to the critical condition,an SI field where FCI sites appeared in the bulk material could be *** this field,thefatigue life of Inconel 718 samples could be improved by approximately 140%.

关键词： surface integrity fatigue strength Inconel 718 ultrasonic assisted grinding

Effect of Room Temperature Ultrasonic Vibration Compression on the Microstructure Evolution and Mechanical Properties of AZ91 Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1135-1146页

作者： Ziyue Xu Huan Liu Luyao Li Chao Sun Xi Tan Baishan Chen Qiangsheng Dong Yuna Wu Jinghua Jiang Jiang Ma College of materials Science and Engineering Hohai UniversityNanjing210000China Suzhou Research Institute of Hohai University Suzhou215000China shenzhen key laboratory of high performance Nontraditional manufacturing College of Mechatronics and Control EngineeringShenzhen UniversityShenzhen518060China Institute of Medical Devices(Suzhou) Southeast UniversitySuzhou215163China Institute for Advanced Study Central South UniversityChangsha410083China Jiangsu key laboratory of Advanced Structural materials and Application Technology Nanjing Institute of TechnologyNanjing211167China

To investigate the potential of direct ultrasonic vibration on improving the performance of magnesium alloys,this study first employed the ultrasonic vibration compression(UVC)on the solid solution treated AZ91 alloy,and explored its microstructure evolution and mechanical properties under *** only two seconds,the UVC alloys showed large deformation strains of 34.8–54.4%,and sudden increase of sample temperature to 243℃.Microstructure characterizations proved that UVC promoted the formation of abundant shear bands,fine grains,and the bimodal distribution of Mg17Al12 precipitates consisting of submicron particles located within the shear bands and nano-sized ones within the *** to the unique microstructure,the micro-hardness(and nano-hardness)value of UVC alloy was increased by 37.7%(35%)when compared with the solution-treated ***,the nano-modulus of the developed AZ91 alloy was also significantly increased to 62 GPa by statistical nanoindentation tests,which could be ascribed to increased Mg_(17)Al_(12) precipitates and decreased c/a value to some *** general,this work provides a new insight into the design and preparation of high-performance magnesium alloys by UVC at room temperature.

关键词： AZ91 alloys Ultrasonic vibration compression Precipitation Shear bands Mechanical properties

Ag-doped CNT/HAP nanohybrids in a PLLA bone scaffold show significant antibacterial activity

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Bio-Design and manufacturing 2024年第2期7卷 105-120页

作者： Cijun Shuai Xiaoxin Shi Kai Wang Yulong Gu Feng Yang Pei Feng State key laboratory of Precision manufacturing for Extreme Service performance College of Mechanical and Electrical EngineeringCentral South UniversityChangsha 410083China Institute of additive manufacturing Jiangxi University of Science and TechnologyNanchang 330013China College of Mechanical Engineering Xinjiang UniversityUrumqi 830017China

Bacterial infection is a major problem following bone implant ***,poly-l-lactic acid/carbon nanotube/hydroxyapatite(PLLA/CNT/HAP)bone scaffolds possess enhanced mechanical properties and show good ***,wesynthesizedsilver(Ag)-dopedCNT/HAP(CNT/Ag-HAP)nanohybrids via the partial replacing of calcium ions(Ca2+)in the HAP lattice with silver ions(Ag+)using an ion doping technique under hydrothermal ***ﬁcally,the doping process was induced using the special lattice structure of HAP and the abundant surface oxygenic functional groups of CNT,and involved the partial replacement of Ca2+in the HAP lattice by doped Ag+as well as the in situ synthesis of Ag-HAP nanoparticles on CNT in a hydrothermal *** result-ing CNT/Ag-HAP nanohybrids were then introduced into a PLLA matrix via laser-based powder bed fusion(PBF-LB)to fabricate PLLA/CNT/Ag-HAP scaffolds that showed sustained antibacterial *** then found that Ag+,which pos-sesses broad-spectrum antibacterial activity,endowed PLLA/CNT/Ag-HAP scaffolds with this activity,with an antibacterial effectiveness of 92.65%.This antibacterial effect is due to the powerful effect of Ag+against bacterial structure and genetic material,as well as the physical destruction of bacterial structures due to the sharp edge structure of *** addition,the scaffold possessed enhanced mechanical properties,showing tensile and compressive strengths of 8.49 MPa and 19.72 MPa,***,the scaffold also exhibited good bioactivity and cytocompatibility,including the ability to form apatite layers and to promote the adhesion and proliferation of human osteoblast-like cells(MG63 cells).

关键词： Ag-doped Carbon nanotube/hydroxyapatite(CNT/HAP) Antibacterial properties Bone scaffold

Unveiling strain-enhanced moiréexciton localization in twisted van der Waals homostructures

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Nano Research 2024年第4期17卷 3245-3252页

作者： Henry Rui He Haihong Zheng Biao Wu Shaofei Li Junnan Ding Zongwen Liu Jian-Tao Wang Anlian Pan Yanping Liu Institute of Quantum Physics School of PhysicsCentral South UniversityChangsha 410083China State key laboratory of Precision manufacturing for Extreme Service performance Central South UniversityChangsha 410083China School of Chemical and Biomolecular Engineering The University of SydneyNSW 2006Australia Beijing National laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China College of materials Science and Engineering Hunan UniversityChangsha 410082China State key laboratory of high-performance Complex manufacturing Central South UniversityChangsha 410083China shenzhen Research Institute of Central South University Shenzhen 51800China

Moirésuperlattices,arising from the controlled twisting of van der Waals homostructures at specific angles,have emerged as a promising platform for quantum emission ***,the manipulation of strain provides a versatile strategy to finely adjust electronic band structures,enhance exciton luminescence efficiency,and establish a robust foundation for two-dimensional quantum light ***,the intricate interplay between strain and moirépotential remains partially ***,we introduce a meticulously designed fusion of strain engineering and the twisted 2L-WSe_(2)/2L-WSe_(2) homobilayers,resulting in the precise localization of moiré*** low-temperature photoluminescence spectroscopy,we unveil the emergence of highly localized moiré-enhanced emission,characterized by the presence of multiple distinct emission ***,our investigation demonstrates the effective regulation of moirépotential depths through strain engineering,with the potential depths of strained and unstrained regions differing by 91%.By combining both experimental and theoretical approaches,our study elucidates the complex relationship between strain and moirépotential,thereby opening avenues for generating strain-induced moiréexciton single-photon sources.

关键词： moirésuperlattices strain engineering moiréexcitons moirépotential