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Simultaneously enhancing the strength and ductility of as-extruded AlN/AZ91 composites via nano-precipitation and pyramidal slip

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Journal of Materials Science & Technology 2024年第5期172卷 240-254页

作者： Bin Zhang Yunxia Sun Tuo Liang Yunzhen Li Tian Li Jingchao Wang Ruiru Cai changlin yang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

Age hardening is often used to optimize the mechanical properties of as-deformed Mg-based materials in industry,whereas the improvement of strength is usually accompanied by the significant loss of ductility,which hinders the application of Mg-based materials in structural components.In the present work,high strength-ductility synergy(the yield strength of 263±9 MPa,ultimate tensile strength of 398±7 MPa and elongation to fracture of 34%±1%)was realized in as-extruded AlN/AZ91 composites after optimiz-ing aging processes.Microstructural characterization shows that AlN particles induced a large number of geometrically necessary dislocations around the AlN/Mg interface during extrusion,which decreased the nucleation barrier and provided more heterogeneous nucleation sites forγ-Mg 17 Al 12 continuous precipi-tation.Meanwhile,95%of residual dislocations in as-extruded AlN/AZ91 composites were annihilated dur-ing peak-aging,suppressing the growth and coarsening of continuous precipitates.Therefore,high density of nano-sizedγ-Mg 17 Al 12 continuous precipitates was produced in as-extruded AlN/AZ91 composites af-ter peak-aging.During tension,gliding dislocations bypassed sphericalγ-Mg 17 Al 12 nano-precipitates by Orowan looping rather than cutting mechanism,which induced a strong block on dislocation motion.So high yield strength was mainly attributed to the high density of non-shearableγ-Mg 17 Al 12 nano-precipitates with spherical morphology,which was different from other Mg-Al-based systems.The results of texture evolution and slip trace analysis demonstrated that the suppression of extension twinning and less basal slip was due to the enhanced activity of pyramidalc+aslip in as-extruded AlN/AZ91 com-posites after peak-aging during the room temperature tension,meanwhile,the dislocation density of as-extruded AlN/AZ91 composites was significantly decreased during peak-aging,then higher elongation to fracture was achieved.

关键词： Magnesium matrix composites Mechanical properties Precipitation Deformation mechanisms Non-basal slip

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The aging behavior,microstructure and mechanical properties of AlN/AZ91 composite

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镁合金学报(英文) 2023年第7期11卷 2458-2468页

作者： Yunxia Sun changlin yang Bin Zhang Jianfeng Fan Hongxiang Li Tianhao Zhao Jing Li State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’anShaanxi 710072PR China yangtze River Delta Research Institute of NPU TaicangJiangsu 215400PR China Key Laboratory of Interface Science and Engineering in Advanced Materials Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024PR China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083PR China

Microstructure evolution and mechanical properties of the aging treated AlN/AZ91 composites were systematically investigated by optical microscopy(OM),high resolution scanning electron microscopy(HRSEM)with an energy dispersive spectrum(EDS),and high-angle annular dark field scanning transmission electron microscopy(HAADF-STEM).The results show that the higher fracture elongation(14±1%)and ultimate tensile strength(275±6 MPa)were simultaneously obtained in the peak-aged AlN/AZ91 composites.Comparied with AZ91 matrix alloy,the strength was increased by about 44%and the elongation was approximately five times higher,which mainly attributed to the precipitation of nano-sizedγ-Mg_(17)Al_(12)phase and the activation of non-basal slip systems induced by in-situ AlN particles at room temperature.However,the in-situ formation of AlN reinforcements consumed part of Al element in the matrix alloy,which resulted into the volume fraction decreasing ofγ-Mg_(17)Al_(12)precipitates,and then the age hardening and strengthening efficiency were reduced in the AlN/AZ91 composites.On the other hand,the mismatch of thermal expansion coefficient between AlN particles and AZ91 matrix generated high density dislocations around AlN particles,which promoted the precipitation ofγ-Mg_(17)Al_(12)phase,and then the peak aging time and temperature were decreased.

关键词： Magnesium matrix composites In-situ AlN particles Aging behavior Microstructure Mechanical properties

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A composite absorption liquid for simultaneous desulfurization and denitrification in flue gas

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Chinese Journal of Chemical Engineering 2019年第10期27卷 2566-2573页

作者： Chunlai Liu Jing Li changlin yang Zhenheng Diao Chengxue Wang School of Chemical Engineering Changchun University of TechnologyChangchun 130000China

A composite-liquid absorbent(CLA),NaClO/KMnO4,for simultaneous desulfurization and denitrification(SDD)was studied in a homemade bubbling reactor.The experimental results showed that the CLA configured by sodium hypochlorite(NaClO)and potassium permanganate(KMnO4)had a very good synergistic effect on SDD.The effects of NaClO concentration(CNa),KMnO4 concentration(CK),gas space velocity(Vg),initial p H value,and temperature of the absorption liquid(Ts)on efficiencies of the SDD were investigated.Under the optimal reaction conditions,the best removal efficiencies were 100%for sulfur dioxide(SO2)and above 94%for nitric oxide(NO).The ion chromatography and titration were used to analyze the changes of both the ion species and concentrations in the liquid before and after the reaction.According to the experiment results and related literature,the reaction mechanism of the SDD based on the CLA was proposed.

关键词： Flue gas Absorption Chemical reaction Reaction mechanism NaClO/KMnO4

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Liquid-phase Separation in Rapid Solidification of Undercooled Fe-Co-Cu Melts

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Journal of Materials Science & Technology 2012年第7期28卷 622-625页

作者： Ning Liu Feng Liu Zheng Chen Gencang yang changlin yang Yaohe Zhou School of Metallurgy and Materials Engineering Jiangsu University of Science and Technology Zhangjiagang 215600 China State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xilan 710072 China School of Materials Science and Engineering China University of Mining and Technology Xuzhou 221008 China

The homogeneous liquid was separated into two phases, （Fe, Co）-rich LI and Cu-rich L2, once the melt was undercooled below a liquid-phase separation temperature Tsep. If the duration from Tsep to Tsl （solidification temperature of LI phase）, termed the liquid-phase separation interval Δt, exceeded a critical value, an eggtype structure was observed. By utilizing differential thermal analyses （DTA）, the solidification process of the undercooled Fe-Co-Cu alloys was studied. Additionally, an immiscible boundary was obtained, which was a convex parabola with a symmetrical axis of XCu=0.52. Depending on the relative amounts of LI and L2, the minor phase was nucleated firstly to form liquid droplets and separated from the original liquids at the beginning of liquid-phase separation.

关键词： Undercooled Fe-Co-Cu alloys Egg-type structure Liquid-phase separation

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Investigation of the 12 orientations variants of nanoscale Al precipitates in eutectic Si of Al-7Si-0.6Mg alloy

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Journal of Materials Science & Technology 2021年第8期67卷 186-196页

作者： Yifan Wang Yanli Lu Jing Zhang Wenchao yang changlin yang Pan Wang Xiaoqing Song Zheng Chen State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityYouyiXi Road 127Xi’an710072China

Various orientations and diffraction patterns from nanoscale Al precipitates in eutectic Si were investigated by high-resolution transmission electron microscopy combined with transition matrix and stereographic projection.It was found that the Al precipitates had 12 variants,all orientation relationships can be expressed as:(001)Al//{111}Si,[110]Al//Si.Further,a new diffraction pattern model from Al precipitates was established under[111]Si zone axis,which was in good agreement with the experiment data.The microstructure,adhesion strength and electronic structure of the interface between Al precipitate and Si matrix were studied by first-principles calculation and experimental observation.The results show that the covalent bonds are formed between interfacial Al and Si atoms,which play a key role in interfacial bind strength.Based on the Griffith fracture theory,the cracks tend to form and expand in the interior of Al precipitates firstly,and the interfaces can act as a protective layer to prevent crack propagation.Therefore,the nanoscale Al precipitates will improve the toughness of eutectic Si particles by releasing part of stress through lattice distortion.In addition,the stretched nanoscale Al precipitates can act as effective heterogeneous nucleation sites for high density deformation nanotwins in eutectic Si during deformation,which significantly improved the deformability of eutectic Si.

关键词： Aluminum precipitates Silicon particles High-resolution transmission electron microscopy Strengthening mechanism First-principles

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Age hardening responses of as-extruded Mg-2.5Sn-1.5Ca alloys with a wide range of Al concentration

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Journal of Materials Science & Technology 2020年第3期38卷 39-46页

作者： Qiuyan Huang yang Liu Aiyue Zhang Haoxin Jiang Hucheng Pan Xiaohui Feng changlin yang Tianjiao Luo Yingju Li Yuansheng yang Institute of Metal Research Chinese Academy of SciencesShenyang110016China Key Laboratory for Anisotropy and Texture of Materials(MOE) School of Materials Science and EngineeringNortheastern UniversityShenyang110819China Research Center for Metallic Wires Northeastern UniversityShenyang110819China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an710072China

This article aims to explore the age hardening responses of both as-extruded and as-aged Mg-2.5 Sn-1.5 Ca-x Al alloys(x=2.0,4.0 and 9.0 wt%,termed TXA322,TXA324 and TXA329,respectively)through microstructural and mechanical characterization.Results indicate that grain size of as-extruded TXA322,TXA324 and TXA329 alloys were^16μm,~10μm and^12μm,respectively.A number ofanddislocations were observed in all the as-extruded samples.Guinier–Preston(GP)zones were evidently identified in TXA322 alloy,while only a small number of Mg17 Al12 phases existed in both TXA324 and TXA329 alloys.An aging treatment facilitated the precipitation of a high number density of GP zones within the matrix of TXA322 alloy.In contrast,no obvious nano-precipitates were in as-aged TXA324 alloy.Numerous nano-Mg17 Al12 phases were formed through a following aging treatment in TXA329 alloy.In terms of mechanical properties,it is apparent that an increment in ultimate tensile strength of^46 MPa and^40 MPa was yielded in peak-aged TXA322 and TXA329 alloys,while no obvious variations in UTS were present in peak-aged TXA324 alloy,in comparison with the as-extruded counterparts.

关键词： Magnesium alloys Age hardening Precipitations Dislocations Mechanical properties

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面向航空电子产品的电子装联工艺设计系统开发

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现代信息科技 2024年第12期8卷 85-90,95页

作者：杨昌霖中国航空工业集团公司西安航空计算技术研究所陕西西安710076

针对传统电子装联工艺设计系统缺乏元器件库与知识库、图片及文字处理能力较弱的问题,提出了电子装联工艺设计模型,开发了面向航空电子产品的电子装联工艺设计系统,并介绍了系统框架,数据接口的用法以及使用效果。实践表明,电子装联工... 详细信息

针对传统电子装联工艺设计系统缺乏元器件库与知识库、图片及文字处理能力较弱的问题,提出了电子装联工艺设计模型,开发了面向航空电子产品的电子装联工艺设计系统,并介绍了系统框架,数据接口的用法以及使用效果。实践表明,电子装联工艺设计模型可以有针对性地为操作人员提供有指导性的工艺信息。通过调用MFC提供的数据接口可以实现图片及文字的灵活排版、工艺知识的可视化表达、文件传输以及视频播放功能。

关键词：航空电子产品电子装联工艺设计系统 MFC

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基于决策树求解非线性规划问题的算法

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信息技术与信息化 2024年第3期 95-98页

作者：杨昌霖中国航空工业集团公司西安航空计算技术研究所陕西西安710064

针对群体智能优化算法具有随机性、盲目性、可编程性差的问题,提出了一种简单有效且不具有随机性的全局搜索算法,用于求解非线性规划问题。通过对每个决策变量的可行域离散化处理后得到的数据构建决策树,采用深度优先的规则对最优解进... 详细信息

针对群体智能优化算法具有随机性、盲目性、可编程性差的问题,提出了一种简单有效且不具有随机性的全局搜索算法,用于求解非线性规划问题。通过对每个决策变量的可行域离散化处理后得到的数据构建决策树,采用深度优先的规则对最优解进行搜索,搜索的同时用指数衰减函数调整搜索步长,从而逐步缩小搜索范围,直到结果收敛。算法不具有随机性,不需要编码、解码、交叉、变异等复杂操作,也不需要随机生成初始种群,可编程性强。对非线性规划的六个测试函数进行求解,并与文献中报道的结果对比,结果表明基于决策树的遍历搜索对解决非线性规划问题有效,对于多决策变量的复杂优化问题,采用分组搜索的策略既能保证求解精度,也能保证收敛速度。

关键词：非线性规划决策树搜索算法最优化

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Effect of extrusion speed on microstructure and mechanical properties of the Mg-Ca binary alloy

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Journal of Magnesium and Alloys 2021年第4期9卷 1304-1310页

作者： Jingren Li Aiyue Zhang Hucheng Pan Yuping Ren Zhuoran Zeng Qiuyan Huang changlin yang Lifeng Ma Gaowu Qin Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819China Department of Materials Science and Engineering Monash UniversityVic.3800Australia Institute of Metal Research Chinese Academy of SciencesShenyang 110016China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’anShaanxi 710072China Shanxi Provincial Key Laboratory of Metallurgical Equipment Design and Technology Taiyuan University of Science and TechnologyTaiyuan 030024China

This work reported the effect of extrusion speeds on the microstructures and mechanical properties of Mg-Ca binary alloy.The results showed that yield strength of the as-extruded Mg-1.2wt.%Ca alloys decrease from∼360MPa to∼258MPa as the ram speed increases from 0.4mm/s to 2.4 mm/s,and the elongation increases from∼3.9%to∼12.2%.The microstructure changes from bimodal grain feature to the complete dynamical recrystallization(DRX)with increase of the extrusion speed.The ultrafine DRXed grains in size of∼0.85μm,the numerous nano-Mg_(2)Ca particles dispersing along the grain boundaries and interiors,as well as the high density of residual dislocations,should account for the high strength.It is believed that the high degree of dynamic recrystallization and the resulting texture randomization play the critical roles in the ductility enhancement of the high-speed extruded Mg alloys.

关键词： Extrusion speed Microstructure Mechanical properties Mg-Ca alloy

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无人驾驶铰接转向车辆路径跟踪控制研究综述

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农业机械学报 2024年第1期55卷 1-21页

作者：祝青园程家琪陈轩伟杨昌霖高云龙邵桂芳厦门大学萨本栋微米纳米科学技术研究院厦门361005

路径跟踪是无人驾驶技术的重要组成部分,是实现铰接转向车辆准确平稳自主行驶的关键,对提高铰接转向车辆在农业、林业、矿山及建筑等行业的作业效率和安全性具有重要意义。车辆模型构建、控制算法设计和算法验证评估是路径跟踪控制研究... 详细信息

路径跟踪是无人驾驶技术的重要组成部分,是实现铰接转向车辆准确平稳自主行驶的关键,对提高铰接转向车辆在农业、林业、矿山及建筑等行业的作业效率和安全性具有重要意义。车辆模型构建、控制算法设计和算法验证评估是路径跟踪控制研究的基础,围绕这3方面阐述了铰接转向车辆路径跟踪控制研究的进展。首先回顾了铰接转向车辆的几何学模型、运动学模型和动力学模型,并讨论了各类模型在路径跟踪控制研究中的适用场景及局限性;在此基础上,阐述了铰接转向车辆路径跟踪控制算法的研究现状,对比并总结了每种算法的优缺点及适用范围,并进一步归纳了算法的验证与评估手段;最后展望了铰接转向车辆路径跟踪技术未来的研究重点及方向:考虑车辆动力学因素及模型参数动态时变特性的车辆建模研究;融合各类算法适应性并结合智能算法的多工况自适应控制算法设计;标准化、流程化的高保真仿真场景开发及集成准确性、稳定性、安全性等多性能的评估方法研究。

关键词：无人驾驶铰接转向车辆路径跟踪控制策略动力学模型验证评估

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