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Laser powder bed fusion of Zr-modified Al-Cu-Mg alloy:Processability and elevated-temperature mechanical properties

Journal of Materials Science & Technology 2023年第5期136卷 223-235页

作者： Yanfang Wang Xin Lin Yufan Zhao Zihong Wang Xiaobin Yu xuehao gao Weidong Huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China

Zr modification is an effective method for improving hot-cracking resistance and elevated-temperature mechanical properties during laser powder bed fusion(L-PBF)of traditional medium and high strength wrought aluminum alloys.This study investigated the l-PBF processability and elevated-temperature mechanical properties of a Zr-modified 2024Al alloy.It was found that the hot-cracking susceptibility increased with the increased scanning speed,which was in reasonable agreement with the modified Rappaz-Drezet-Gremaud criterion.Furthermore,the primary L1_(2)-Al_(3)Zr precipitates,which acted as ef-ficient nucleation sites,precipitated at the fusion boundary of the melt pool,leading to the formation of a heterogeneous grain structure.The yield strength(YS)of the as-fabricated samples at 150,250,and 350℃was 363,210,and 48 MPa,respectively.Despite the slight decrease to 360 MPa of the YS when tested at 150℃,owing to the additional precipitate strengthening from the L1_(2)-Al_(3)Zr precipitates,the YS achieved yield strengths of 253 and 69 MPa,an increase of 20.5%and 30.4%,when tested at 250 and 350℃,respectively.The yield strengths in both the as-fabricated and T6-treated conditions tested at 150 and 250℃were comparable to those of casting Al-Cu-Mg-Ag alloys and superior to those of traditionally heat-resistant 2219-T6 and 2618-T6 of Al-Cu alloys.

关键词： Laser powder bed fusion Zirconium Al-Cu-Mg alloy Processability Elevated-temperature mechanical property

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Laser-based directed energy deposition of novel Sc/Zr-modified Al-Mg alloys:columnar-to-equiaxed transition and aging hardening behavior

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Journal of Materials Science & Technology 2021年第10期69卷 168-179页

作者： Zihong Wang Xin Lin Yao Tang Nan Kang xuehao gao Shuoqing Shi Weidong Huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi'an 710072China

The control of grain morphology is important in laser additive manufacturing(LAM),as grain morphology further affects the hot cracking resistance,anisotropy,and strength–ductility synergy of materials.To develop a solidification-control solution and achieve columnar-to-equiaxed transition(CET)in Al-based alloys during LAM,Sc-and-Zr-modified Al-Mg alloys were processed via directed energy deposition(DED).CET was achieved by introducing high potent primary Al_(3)(Sc,Zr)nucleation sites ahead of the solidification interface.Furthermore,the relationship between the solidification control parameters and precipitation behavior of primary Al_(3)(Sc,Zr)nucleation sites was established using the time-dependent nucleation theory.Then,the CET was studied according to the Hunt criterion.The results indicated that coarse columnar grain structure was still obtained at the inner region of the molten pool at low Sc/Zr contents owing to the effective suppression of the precipitation of the primary Al_(3)(Sc,Zr)nucleation sites via rapid solidification during DED.In addition,the relatively low melt temperature at the fusion boundary unavoidably promoted the precipitation of primary Al_(3)(Sc,Zr)nucleation sites,which resulted in a fine equiaxed grains band at the edge of the molten pool.As the Sc/Zr content increased,the solidification cooling rate was not sufficient to suppress the precipitation of the primary Al_(3)(Sc,Zr)nucleation sites,and a fully equiaxed grain structure was obtained.Furthermore,the effect of the layer-by-layer manufacturing process on the subsequent precipitation strengthening of secondary Al_(3)(Sc,Zr)precipitates was discussed.Both the remelting and subsequent aging during thermal cycling should be considered to achieve greater precipitation strengthening.

关键词： Al-Mg-Sc-Zr alloys Additive manufacturing Directed energy deposition Columnar-to-equiaxed transition Phase precipitation

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Effect of Cu content on microstructure and mechanical properties of in-situ β phases reinforced Ti/Zr-based bulk metallic glass matrix composite by selective laser melting(SLM)

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Journal of Materials Science & Technology 2021年第8期67卷 174-185页

作者： xuehao gao Xin Lin Qiaodan Yan Zihong Wang Xiaobin Yu Yinghui Zhou Yunlong Hu Weidong Huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MUT ChinaNorthwestern Polytechnical UniversityXi'an710072China

In this study,non-toxic in-situβphases of reinforced Ti/Zr-based bulk metallic glass matrix composites(BMGCs)of(Ti_(0.65)Zr_(0.35))100-xCux(x=5,10,15 at.%)are fabricated via selective laser melting.The effect of Cu content on phase formation,microstructure,and mechanical properties is investigated.The average volume fraction and width of theβphase decreases with increasing Cu content,while a more amorphous phase and the(Ti,Zr)_(2)Cu phase forms.In the center zone of the molten pool,theβphase grows in the direction of the temperature gradient,and the amorphous phase distributes among theβphases.This occurs using:sphere morphology(for x=5),a more continuous elongated sphere and network morphology(for x=10),and network morphology(for x=15),respectively.In the edge zone of the molten pool,due to the smaller cooling rate and the existence of a partially molten zone,theβphase becomes coarser,and an amorphous phase forms for more continuous networks.Furthermore,the hardness improves significantly with increasing Cu content.No crack is found for x=5.Although the average volume fraction of theβphase for x=5 is about 90%,the compression yield strength is 1386±64 MPa,reaching to an average level of conventionally fabricated counterparts,due to finer microstructure,and twinning and martensitic transformation of theβphase.

关键词： Metallic glass Amorphous phase βPhase Bulk metallic glass matrix composites(BMGCs) Additive manufacturing(AM) Selective laser melting(SLM)

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Microstructure and compressive/tensile characteristic of large size Zr-based bulk metallic glass prepared by laser solid forming

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Journal of Materials Science & Technology 2019年第2期35卷 328-335页

作者： Xin Lin Yuanyuan Zhang gaolin Yang xuehao gao Qiao Hu Jun Yu Lei Wei Weidong Huang State Key Laboratory of Solidification Processing Northwestern Polytechnical University Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT China Northwestern Polytechnical University

The large size, crack-free Zr_(55)Cu_(30)Al_(10)Ni_(5) bulk metallic glass(BMGs) with the diameter of 54 mm and the height of 15 mm was built by laser solid forming additive manufacturing technology, whose size is larger than the critical diameter by casting. The microstructure, tensile and compressive deformation behaviors and fracture morphology of laser solid formed Zr_(55)Cu_(30)Al_(10)Ni_5 BMGs were investigated. It is found that the crystallization mainly occurs in the heat-affected zones of deposition layers, which consist of Al_5Ni_3Zr_2, NiZr_2, ZrCu, CuZr_2 phases. The content of amorphous phase in the deposit is about 63%.Under the compressive loading, the deposit presents no plasticity before fracture occurs. The fracture process is mainly controlled by the shear stress and the compressive shear fracture angles of about39?. The compressive strength reaches 1452 MPa, which is equivalent to that of as-Cast Zr_(55)Cu_(30)Al_(10)Ni_5 BMGs, and there exist vein-like patterns, river-like patterns and smooth regions at the compressive fractography. Under the tensile loading, the deposit presents the brittle fracture pattern without plastic deformation. The fracture process exhibits normal fracture model, and the tensile shear fracture angle of about 90?. The tensile strength is only about 609 MPa, and the tensile fractography mainly consists of micro-scaled cores and vein-like patterns, dimple-like patterns, chocolate-like patterns and smooth regions. The results further verified the feasibility and large potential of laser additive manufacturing on fabrication and industrial application of large-scale BMGs parts.

关键词： Zr-based bulk metallic glass Laser solid forming Additive manufacturing Microstructure Compressive and tensile behavior

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Novel strategy of multidimensional information encryption via multi-color carbon dots aggregation-induced emission

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Nano Research 2024年第6期17卷 5680-5687页

作者： Liu Ding Xilang Jin Yuchong gao Shouwang Kang Haiyan Bai xuehao Ma Taotao Ai Hongwei Zhou Weixing Chen Shaanxi Key Laboratory of Photoelectric Functional Materials and Devices Engineering Research Center of Light Stabilizers for Polymer Materials Universities of Shaanxi Province School of Materials and Chemical EngineeringXi’an Technological UniversityXi’an 710021China School of Material Science and Engineering Shaanxi University of TechnologyHanzhong 723000China Department of Materials Science and Engineering University of PennsylvaniaPhiladelphia 19104USA

Carbon dots(CDs)with aggregation-induced emission(AIE)have sparked significant interest in multidimensional anti-counterfeiting due to their exceptional fluorescence properties.However,the preparation of AIE CDs with multicolor solid-state fluorescence remains a formidable challenge due to its complicated construction.In the present work,a novel class of multicolor AIE CDs(M-CDs)were fabricated using selected precursor(salicylic acid,thiosalicylic acid,and 2,2'-dithiodibenzoic acid),with an eco-friendly,low-cost one-pot solvothermal method.In the dilute organic solution,M-CDs manifested blue emission,but upon aggregation in the presence of water,the red,yellow,green,and blue emissions were displayed due to the AIE effect.Structural analysis,coupled with theoretical calculations,revealed that the increase in the size of sp2 domains would lower the Eg and cause a red-shift emission wavelength.Significantly,the continuous emission of M-CDs from blue to red can be utilized as ink for multimode printing,enabling the creation of a variety of school badges and quick response codes.These findings hold promising implications for multi-information encryption applications.

关键词： aggregation-induced emission(AIE) luminescence mechanism multi-color emission information encryption.

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激光多材料增材制造技术研究进展和展望

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航空制造技术 2023年第8期66卷 26-34页

作者：韦超杨潇鲁淑芬程东旭高学浩袁丁中国科学院宁波材料技术与工程研究所宁波315201

以航空航天为代表的极端使役零部件工作环境严酷,结构复杂,功能集成。多材料增材制造(Multi-material additive manufacturing,MMAM)能够满足特殊区域的宏观性能定制化和结构—功能一体化,在核能、军事、航空和医疗等领域具有极大的应... 详细信息

以航空航天为代表的极端使役零部件工作环境严酷,结构复杂,功能集成。多材料增材制造(Multi-material additive manufacturing,MMAM)能够满足特殊区域的宏观性能定制化和结构—功能一体化,在核能、军事、航空和医疗等领域具有极大的应用潜力。重点阐述了MMAM技术影响界面结合强度的主要因素及消除缺陷的方法;介绍了目前MMAM技术不同的送粉方法和每种送粉方法的优缺点;讨论了工艺参数对MMAM技术的影响规律;最后总结MMAM技术目前的瓶颈性难题,展望了未来的主要研究方向。

关键词：多材料增材制造(MMAM) 界面结合工艺参数送粉系统缺陷抑制

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基于改进人工势场法的救灾机器人路径规划

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工矿自动化 2016年第9期42卷 37-42页

作者：田子建高学浩中国矿业大学(北京)机电与信息工程学院北京100083

针对矿井障碍物复杂多变、救灾机器人采用传统人工势场法进行路径规划易陷入局部极小点的问题,提出一种基于改进人工势场法的救灾机器人路径规划方法。该方法通过在引力场中加入扰动场来改变引力场函数,使救灾机器人在陷入局部极小点时... 详细信息

针对矿井障碍物复杂多变、救灾机器人采用传统人工势场法进行路径规划易陷入局部极小点的问题,提出一种基于改进人工势场法的救灾机器人路径规划方法。该方法通过在引力场中加入扰动场来改变引力场函数,使救灾机器人在陷入局部极小点时自主走出局部极小点;结合障碍填充法,通过对凹障碍物进行虚拟填充,形成新的障碍物并产生相应的斥力场函数,避免救灾机器人再次陷入局部极小点。仿真及测试结果验证了该方法的可行性及有效性。

关键词：救灾机器人路径规划人工势场法扰动场势场函数障碍物填充法

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运营铁路隧道套衬施工机械化配套研究与应用

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隧道建设（中英文） 2024年第2期44卷 368-376页

作者：田雪豪宋丹江帅付开勇高立君王柏松中铁工程装备集团隧道设备制造有限公司河南新乡453000

为解决运营铁路隧道衬砌病害治理施工安全系数低、劳动强度大、施工人员需求多、施工质量参差不齐的问题,调研分析套衬加固病害整治工法、施工设备需求及铁路在轨运行设备规范,研究设备配套技术,形成一套适用于运营铁路隧道套衬施工的... 详细信息

为解决运营铁路隧道衬砌病害治理施工安全系数低、劳动强度大、施工人员需求多、施工质量参差不齐的问题,调研分析套衬加固病害整治工法、施工设备需求及铁路在轨运行设备规范,研究设备配套技术,形成一套适用于运营铁路隧道套衬施工的机械化装备及施工组织方案,并在某高铁隧道套衬工程中试点应用。应用结果表明:1)该成套设备利用运营天窗点的有限时间进行作业,具有集成化、模块化、机械化、专业化的特点;2)该成套设备实现了在作业人员减少一半以上的情况下工效提高2倍以上的目标;3)应急解决预案可靠有效,可实现对突发状况的处理。

关键词：运营铁路隧道套衬机械化衬砌病害整治

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V型夹层炸药干扰杆式侵彻体的影响因素研究

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弹箭与制导学报 2014年第1期34卷 87-89,94页

作者：高学浩王凤英刘天生薛小秀中北大学化工与环境学院太原030051 山西江阳化工有限公司太原030041

为提高爆炸式反应装甲对杆式侵彻体的防护能力,加强对V型夹层炸药干扰杆式侵彻体的研究,利用数值模拟软件LS-DYNA分析入射角θ、两平板炸药间距离H1、V型夹层炸药距主装甲距离H2等因素对V型夹层炸药干扰杆式侵彻体的影响。结果表明,随... 详细信息

为提高爆炸式反应装甲对杆式侵彻体的防护能力,加强对V型夹层炸药干扰杆式侵彻体的研究,利用数值模拟软件LS-DYNA分析入射角θ、两平板炸药间距离H1、V型夹层炸药距主装甲距离H2等因素对V型夹层炸药干扰杆式侵彻体的影响。结果表明,随着θ增加,V型夹层炸药的干扰作用不断加强,并且当θ=60°时,干扰作用突然跃升;随着H1增加,干扰作用先加强,然后又下降;随着H2增加,干扰作用先保持不变,然后稍微加强,之后又保持不变。

关键词： V型夹层炸药爆炸式反应装甲杆式侵彻体干扰

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大气科学原始创新的学科背景视角

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气象科技进展 2014年第6期4卷 46-49页

作者：高学浩陈正洪中国气象局气象干部培训学院北京100081

基于气象科技史的研究,探索大气科学发展的某些创新规律,通过对比分析揭示出数学和物理等理科背景对于大气科学的原始创新具有重要作用。这种规律与大气科学自身发展有密切关系,也是大气科学本质决定的。分析表明学科背景规律对人才培... 详细信息

基于气象科技史的研究,探索大气科学发展的某些创新规律,通过对比分析揭示出数学和物理等理科背景对于大气科学的原始创新具有重要作用。这种规律与大气科学自身发展有密切关系,也是大气科学本质决定的。分析表明学科背景规律对人才培养有重要借鉴和启示。

关键词：气象科技史学科背景原始创新人才培养

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