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增材制造 7

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alloying of CoCrFeMnNi high-entropy alloy from elemental feedstock toward high-throughput synthesis via laserpowder bed fusion

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0727-x

摘要： High-entropy alloys (HEAs) are considered alternatives to traditional structural materials because of their superior mechanical, physical, and chemical properties. However, alloy composition combinations are too numerous to explore. Finding a rapid synthesis method to accelerate the development of HEA bulks is imperative. Existing in situ synthesis methods based on additive manufacturing are insufficient for efficiently controlling the uniformity and accuracy of components. In this work, laser powder bed fusion (L-PBF) is adopted for the in situ synthesis of equiatomic CoCrFeMnNi HEA from elemental powder mixtures. High composition accuracy is achieved in parallel with ensuring internal density. The L-PBF-based process parameters are optimized; and two different methods, namely, a multi-melting process and homogenization heat treatment, are adopted to address the problem of incompletely melted Cr particles in the single-melted samples. X-ray diffraction indicates that HEA microstructure can be obtained from elemental powders via L-PBF. In the triple-melted samples, a strong crystallographic texture can be observed through electron backscatter diffraction, with a maximum polar density of 9.92 and a high ultimate tensile strength (UTS) of (735.3 ± 14.1) MPa. The homogenization heat-treated samples appear more like coarse equiaxed grains, with a UTS of (650.8 ± 16.1) MPa and an elongation of (40.2% ± 1.3%). Cellular substructures are also observed in the triple-melted samples, but not in the homogenization heat-treated samples. The differences in mechanical properties primarily originate from the changes in strengthening mechanism. The even and flat fractographic morphologies of the homogenization heat-treated samples represent a more uniform internal microstructure that is different from the complex morphologies of the triple-melted samples. Relative to the multi-melted samples, the homogenization heat-treated samples exhibit better processability, with a smaller composition deviation, i.e., ≤ 0.32 at.%. The two methods presented in this study are expected to have considerable potential for developing HEAs with high composition accuracy and composition flexibility.

关键词： laser powder bed fusion (L-PBF)     in situ alloying     high-entropy alloys     heat treatment     rapid synthesis    

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Orientation effect of electropolishing characteristics of 316L stainless steel fabricated by laser powderbed fusion

《机械工程前沿（英文）》 2021年 第16卷 第3期   页码 580-592 doi: 10.1007/s11465-021-0633-7

摘要： 3D metal printing process has attracted increasing attention in recent years due to advantages, such as flexibility and rapid prototyping. This study aims to investigate the orientation effect of electropolishing characteristics on different surfaces of 316L stainless steel fabricated by laser powder bed fusion (L-PBF), considering that the rough surface of 3D printed parts is a key factor limiting its applications in the industry. The electropolishing characteristics on the different surfaces corresponding to the building orientation in selective laser melting are studied. Experimental results show that electrolyte temperature has critical importance on the electropolishing, especially for the vertical direction to the layering plane. The finish of electropolished surfaces is affected by the defects generated during L-PBF process. Thus, the electropolished vertical surface has higher surface roughness Sa than the horizontal surface. The X-ray photoelectron spectroscopy spectra show that the electropolished horizontal surface has higher Cr/Fe element ratio than the vertical surface. The electropolished horizontal surface presents higher corrosion resistance than the vertical surface by measuring the anodic polarization curves and fitting the equivalent circuit of experimental electrochemical impedance spectroscopy.

关键词： electropolishing     laser powder bed fusion     316L stainless steel     corrosion resistance     microstructure    

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Advances in polishing of internal structures on parts made by laser-based powder bed fusion

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0724-0

摘要： The internal structures of metallic products are important in realizing functional applications. Considering the manufacturing of inner structures, laser-based powder bed fusion (L-PBF) is an attractive approach because its layering principle enables the fabrication of parts with customized interior structures. However, the inferior surface quality of L-PBF components hinders its productization progress seriously. In this article, process, basic forms, and applications relevant to L-PBF internal structures are reviewed comprehensively. The causes of poor surface quality and differences in the microstructure and property of the surface features of L-PBF inner structures are presented to provide a perspective of their surface characteristics. Various polishing technologies for L-PBF components with inner structures are presented, whereas their strengths and weaknesses are summarized along with a discussion on the challenges and prospects for improving the interior surface quality of L-PBF parts.

关键词： laser-based powder bed fusion     polishing     internal structures     surface quality     surface features     post process     additive manufacturing    

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Development of lunar regolith composite and structure via laser-assisted sintering

《机械工程前沿（英文）》 doi: 10.1007/s11465-021-0662-2

摘要： Aiming at the exploration and resource utilization activities on the Moon, in situ resource utilization and in situ manufacturing are proposed to minimize the dependence on the ground transportation supplies. In this paper, a laser-assisted additive manufacturing process is developed to fabricate lunar regolith composites with PA12/SiO2 mixing powders. The process parameters and composite material compositions are optimized in an appropriate range through orthogonal experiments to establish the relationship of process–structure–property for lunar regolith composites. The optimal combination of composite material compositions and process parameters are mixing ratio of 50/50 in volume, laser power of 30 W, scanning speed of 3500 mm/s, and scanning hatch space of 0.2 mm. The maximum tensile strength of lunar regolith composites reaches 9.248 MPa, and the maximum depth of surface variation is 120.79 μm, which indicates poor powder fusion and sintering quality. Thereafter, the mechanical properties of laser-sintered lunar regolith composites are implemented to the topology optimization design of complex structures. The effectiveness and the feasibility of this laser-assisted process are potentially developed for future lightweight design and manufacturing of the solar panel installed on the lunar rover.

关键词： in situ manufacturing     laser-assisted powder fusion process     mechanical properties     topological structure design    

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一种新型激光打印压缩诱导扭转柔顺机构的成型过程和力学变形行为 Article

高捷, 顾冬冬, 马成龙, 戴冬华, 席丽霞, 林开杰, 高彤, 朱继宏, 杜月欣

《工程（英文）》 2022年 第15卷 第8期   页码 133-142 doi: 10.1016/j.eng.2021.03.032

摘要：

本文采用激光粉末床熔融（LPBF）技术成型了一种基于自由约束拓扑（FACT）方法设计的新型压缩诱导扭转（CIT）柔顺机构。研究了LPBF 打印参数对激光打印CIT 柔顺机构成型性和压缩性能的影响。在375~450 W的优化激光功率范围内，样品的致密化水平均保持在98%以上，所获得的LPBF制造的CIT柔顺机构的相对密度随施加激光功率的变化不明显。增加激光功率有利于消除CIT 柔顺机构斜杆内的残余冶金孔隙。在450 W的激光功率下实现了0.2%的最高尺寸精度和20 μm的最低表面粗糙度。LPBF成型CIT柔顺机构的变形行为表现为四个典型阶段：弹性阶段、非均匀塑性变形阶段、强度破坏阶段和变形破坏阶段（或不稳定变形阶段）。采用450 W激光功率最优成形的CIT 柔顺机构在破坏前的累积压缩应变可达20%，展现了较大的变形能力。通过有限元模拟和实验验证相结合的方法，研究了CIT 柔顺机构的扭转行为和力学性能。在LPBF成型CIT柔顺机构的应变达到15%之前实现了轴向压缩应变与旋转角度之间的近似线性关系。

关键词： 激光3D打印     激光粉末床熔融     压缩诱导扭转柔顺机构     压缩-扭转性能     力学性能    

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微观选择性激光熔化技术发展的现状及未来展望 Review

Balasubramanian Nagarajan, Zhiheng Hu, Xu Song, Wei Zhai, Jun Wei

《工程（英文）》 2019年 第5卷 第4期   页码 702-720 doi: 10.1016/j.eng.2019.07.002

摘要： 选择性激光熔化（SLM）是一种常见的AM技术，它基于粉床熔融法（PBF）来处理金属，但目前只专注于大中型元件的制作。本文综述了微型金属材料SLM的研究现状。

关键词： 增材制造     选择性激光熔化     微细加工     混合处理     粉床重涂    

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Two-dimensional modeling of sintering of a powder layer on top of nonporous substrate

Tiebing CHEN, Yuwen ZHANG,

《机械工程前沿（英文）》 2010年 第5卷 第2期   页码 143-148 doi: 10.1007/s11465-010-0006-0

摘要： Selective laser sintering (SLS) of a two-component metal powder layer on the top of multiple sintered layers by a moving Gaussian laser beam is modeled. The loose metal powder layer is composed of a powder mixture with significantly different melting points. The physical model that accounts the shrinkage induced by melting is described by using a temperature-transforming model. The effects of the porosity and the thickness of the atop loose powder layer with different numbers of the existing sintered metal powder layers below on the sintering process are numerically investigated. The present work will provide a better understanding to simulate much more complicated three-dimensional SLS process.

关键词： laser     sintering     melting     solidification     heat transfer    

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Effect of process parameters on the density and porosity of laser melted AlSi10Mg/SiC metal matrix composite

Omotoyosi H. FAMODIMU, Mark STANFORD, Chike F. ODUOZA, Lijuan ZHANG

《机械工程前沿（英文）》 2018年 第13卷 第4期   页码 520-527 doi: 10.1007/s11465-018-0521-y

摘要：

Laser melting of aluminium alloy—AlSi10Mg has increasingly been used to create specialised products in various industrial applications, however, research on utilising laser melting of aluminium matrix composites in replacing specialised parts have been slow on the uptake. This has been attributed to the complexity of the laser melting process, metal/ceramic feedstock for the process and the reaction of the feedstock material to the laser. Thus, an understanding of the process, material microstructure and mechanical properties is important for its adoption as a manufacturing route of aluminium metal matrix composites. The effects of several parameters of the laser melting process on the mechanical blended composite were thus investigated in this research. This included single track formations of the matrix alloy and the composite alloyed with 5% and 10% respectively for their reaction to laser melting and the fabrication of density blocks to investigate the relative density and porosity over different scan speeds. The results from these experiments were utilised in determining a process window in fabricating near-fully dense parts.

关键词： selective laser melting     additive manufacturing     mechanical alloying     powder metallurgy     aluminium metal matrix composite    

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基于激光粉床熔融镍合金（Inconel 718）加热凝固分析的数值模拟和实验分析

Patcharapit Promoppatum, Shi-Chune Yao, P. Chris Pistorius, Anthony D. Rollett

《工程（英文）》 2017年 第3卷 第5期   页码 685-694 doi: 10.1016/J.ENG.2017.05.023

摘要：
有限元模型和Rosenthal 方程在激光粉床熔融Inconel 718 合金热学现象及微观研究方面具有广泛应用。通过了解 Rosenthal 方程（该方程为有限元分析提供了一种非同寻常的方法）的优点及缺点，研究潜在假设对于估计结果的影响，结合实验对材料物理特性进行对比分析。本文结合有限元模型及 Rosenthal 分析方程预测熔池形状并与文献实验做比较，结果表明这两种方法均能够提供合理准确的估计结果，包括预测出柱状凝固微结构和一次枝晶间距（PDAS）值，与实验结果符合良好。与此同时，基于吸收率选择的灵敏度分析表明，与有限元法相比，Rosenthal 法对吸收率更为敏感，其原因可能是 Rosenthal 法忽略辐射和对流造成的能量流失。

关键词： 增材制造     有限元建模     Rosenthal方程     微结构     物质的热行为     Inconel 718合金    

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Manufacturing cost constrained topology optimization for additive manufacturing

Jikai LIU, Qian CHEN, Xuan LIANG, Albert C. TO

《机械工程前沿（英文）》 2019年 第14卷 第2期   页码 213-221 doi: 10.1007/s11465-019-0536-z

摘要： This paper presents a manufacturing cost constrained topology optimization algorithm considering the laser powder bed additive manufacturing process. Topology optimization for additive manufacturing was recently extensively studied, and many related topics have been addressed. However, metal additive manufacturing is an expensive process, and the high manufacturing cost severely hinders the widespread use of this technology. Therefore, the proposed algorithm in this research would provide an opportunity to balance the manufacturing cost while pursuing the superior structural performance through topology optimization. Technically, the additive manufacturing cost model for laser powder bed-based process is established in this paper and real data is collected to support this model. Then, this cost model is transformed into a level set function-based expression, which is integrated into the level set topology optimization problem as a constraint. Therefore, by properly developing the sensitivity result, the metallic additive manufacturing part can be optimized with strictly constrained manufacturing cost. Effectiveness of the proposed algorithm is proved by numerical design examples.

关键词： topology optimization     manufacturing cost     additive manufacturing     powder bed    

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用于粉末床增材制造的铬镍铁合金粉末特征研究

Quy Bau Nguyen, Mui Ling Sharon Nai, Zhiguang Zhu, Chen-Nan Sun, Jun Wei, Wei Zhou

《工程（英文）》 2017年 第3卷 第5期   页码 695-700 doi: 10.1016/J.ENG.2017.05.012

摘要：

本研究中使用不同的粉末表征技术对铬镍铁合金的原始粉末和回收粉末在粉末床增材制造（AM）上的流动特性、行为特征进行研究。结果发现，选择性激光熔化（SLM）工艺的粒径分布（PSD）范围通常在15 ～ 63 μm 之间。原始的铬镍铁合粉末的流量约为28 s·(50 g)–1，组装密度是60%。流变测试结果表明，原始粉末与回收粉末相比具有更好的流动性。讨论了两种粉末之间的相互关系。运用铬镍铁合金粉末已经成功打印出了螺旋桨。实验结果表明铬镍铁合金粉末适用于增材制造（AM），本研究为生产增材制造粉末提供参考。

关键词： 增材制造     粉末特征     气体雾化     微观结构     铬镍铁合金    

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Large-scale industrial manufacturing of carbon nanotubes in a continuous inclined mobile-bed rotating

Sophie L. Pirard, Sigrid Douven, Jean-Paul Pirard

《化学科学与工程前沿（英文）》 2017年 第11卷 第2期   页码 280-289 doi: 10.1007/s11705-017-1635-1

摘要： This article reports the different steps of the design, development and validation of a process for continuous production of carbon nanotubes (CNTs) via catalytic chemical vapor deposition from the laboratory scale to the industrial production. This process is based on a continuous inclined mobile-bed rotating reactor and very active catalysts using methane or ethylene as carbon source. The importance of modeling taking into account the hydrodynamic, physicochemical and physical phenomena that occur during CNT production in the process analysis is emphasized. The impact of this invention on the environment and human health is taken into consideration too.

关键词： carbon nanotubes     catalytic chemical vapor deposition     inclined rotating reactor     industrial process     scaling-up    

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选区激光熔化纯钨——粉末粒径对激光吸收的影响和扫描轨迹形成机理研究 Article

章佳窈, 顾冬冬, 杨莹, 张红梅, 陈洪宇, 戴冬华, 林开杰

《工程（英文）》 2019年 第5卷 第4期   页码 736-745 doi: 10.1016/j.eng.2019.07.003

摘要：

本文建立了基于线迹追踪的三维激光吸收模型，用于描述选区激光熔化（SLM）成形纯钨粉末时激光束与粉末层的相互作用，研究了粉末粒径大小对粉末激光吸收率和吸收行为的影响。本文给出了激光吸收率、粉层吸收辐照度及其分布、激光扫描轨迹的表面形貌和几何特征（如接触角、宽度和高度，以及重熔深度）之间的内在关系。模拟结果表明，粉末层的吸收率大大超过单一的粉末颗粒或致密平板材料的吸收率。随着粉末粒径增加，粉末层吸收的激光能量减少。当粒径为5 μm时，纯钨粉末层的吸收率最大达到0.6030。激光辐照度在粉床颗粒表面的分布与粒径大小、方位角和粉末在基板上的位置有关。当粒径从5 μm增加到45 μm时，粉末层中的最大辐照度从1.117 × 10–3 W·μm–2降低到0.85 × 10–3 W·μm–2，并且位于中心辐照区域的辐照度分布轮廓逐渐收缩。对SLM纯钨扫描轨迹的表面形貌和横截面几何特征进行了研究，结果验证了模拟的粉末激光吸收行为。该工作对线迹追踪模型预测SLM扫描轨迹润湿性和铺展性的应用提供了科学依据，从而更好地获得优异的激光成形性能。

关键词： 选区激光熔化     钨     线迹追踪模型     吸收率     激光扫描轨迹    

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高功率固体激光装置的发展与工程科学问题

彭翰生,张小民,范滇元,朱健强

《中国工程科学》 2001年 第3卷 第3期   页码 1-8

摘要：

在激光聚变需求牵引下，高功率固体激光技术走过了30多年的发展历程。在世界范围内，美、日、法、中、英、俄等国先后建造了20多台大型装置，输出能量初期仅百焦耳级，后来增大到数万焦耳，固体激光技术得到长足发展。近几年来，几个大国都在建造巨型激光装置，如美国和法国正分别建造国家点火装置NIF和兆焦耳激光器LMJ，我国在研制神光-Ⅲ激光装置，俄国也在计划建造Iskra-6激光装置。这一代激光装置的研制不但在科学技术上提出了许多新需求，从而把激光科学技术发展推向新的历史阶段，而且就其规模、投入、周期和风险而言，是前所未有的大光学科学工程。从工程科学的角度去研究如何才能建造出性能优良和效费比高的巨型激光装置是需要回答的具有挑战性的新课题。

关键词： 激光聚变     高功率固体激光     发展趋势     工程科学     创新    

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Influence of the field humiture environment on the mechanical properties of 316L stainless steel repaired

Lianzhong ZHANG, Dichen LI, Shenping YAN, Ruidong XIE, Hongliang QU

《机械工程前沿（英文）》 2018年 第13卷 第4期   页码 513-519 doi: 10.1007/s11465-018-0503-0

摘要：

The mechanical properties of 316L stainless steel repaired with Fe314 under different temperatures and humidities without inert gas protection were studied. Results indicated favorable compatibility between Fe314 and 316L stainless steel. The average yield strength, tensile strength, and sectional contraction percentage were higher in repaired samples than in 316L stainless steel, whereas the elongation rate was slightly lower. The different conditions of humiture environment on the repair sample exerted minimal influence on tensile and yield strengths. The Fe314 cladding layer was mainly composed of equiaxed grains and mixed with randomly oriented columnar crystal and tiny pores or impurities in the tissue. Results indicated that the hardness value of Fe314 cladding layer under different humiture environments ranged within 419–451.1 HV0.2. The field humiture environment also showed minimal impact on the average hardness of Fe314 cladding layers. Furthermore, 316L stainless steel can be repaired through laser cladding by using Fe314 powder without inert gas protection under different temperatures and humidity environments.

关键词： laser cladding     repaired performance     tensile strength     temperature and humidity environment    

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标题 作者 时间 类型 操作

alloying of CoCrFeMnNi high-entropy alloy from elemental feedstock toward high-throughput synthesis via laserpowder bed fusion

期刊论文

Orientation effect of electropolishing characteristics of 316L stainless steel fabricated by laser powderbed fusion

期刊论文

Advances in polishing of internal structures on parts made by laser-based powder bed fusion

期刊论文

Development of lunar regolith composite and structure via laser-assisted sintering

期刊论文

一种新型激光打印压缩诱导扭转柔顺机构的成型过程和力学变形行为

高捷, 顾冬冬, 马成龙, 戴冬华, 席丽霞, 林开杰, 高彤, 朱继宏, 杜月欣

期刊论文

微观选择性激光熔化技术发展的现状及未来展望

Balasubramanian Nagarajan, Zhiheng Hu, Xu Song, Wei Zhai, Jun Wei

期刊论文

Two-dimensional modeling of sintering of a powder layer on top of nonporous substrate

Tiebing CHEN, Yuwen ZHANG,

期刊论文

Effect of process parameters on the density and porosity of laser melted AlSi10Mg/SiC metal matrix composite

Omotoyosi H. FAMODIMU, Mark STANFORD, Chike F. ODUOZA, Lijuan ZHANG

期刊论文

基于激光粉床熔融镍合金（Inconel 718）加热凝固分析的数值模拟和实验分析

Patcharapit Promoppatum, Shi-Chune Yao, P. Chris Pistorius, Anthony D. Rollett

期刊论文

Manufacturing cost constrained topology optimization for additive manufacturing

Jikai LIU, Qian CHEN, Xuan LIANG, Albert C. TO

期刊论文

用于粉末床增材制造的铬镍铁合金粉末特征研究

Quy Bau Nguyen, Mui Ling Sharon Nai, Zhiguang Zhu, Chen-Nan Sun, Jun Wei, Wei Zhou

期刊论文

Large-scale industrial manufacturing of carbon nanotubes in a continuous inclined mobile-bed rotating

Sophie L. Pirard, Sigrid Douven, Jean-Paul Pirard

期刊论文

选区激光熔化纯钨——粉末粒径对激光吸收的影响和扫描轨迹形成机理研究

章佳窈, 顾冬冬, 杨莹, 张红梅, 陈洪宇, 戴冬华, 林开杰

期刊论文

高功率固体激光装置的发展与工程科学问题

彭翰生,张小民,范滇元,朱健强

期刊论文

Influence of the field humiture environment on the mechanical properties of 316L stainless steel repaired

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