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Improving Densification and Mechanical Properties of FeAl/TiC Composites by Addition of Ni

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Journal of Materials Science & Technology 2003年第1期19卷 73-76页

作者： Yong LIU, Fengxiao LIU, Baiyun HUANG, kechao zhou, Yuehui HE and Zhihong TANGNational Key Lab for P/M, Central South University, Changsha 410083, China Lab. for P/M Central South Univ. Changsha 410083 China

FeAl/TiC composites were fabricated by hot pressing blended elemental powders. The effects of Ni-doping on thedensification and mechanical properties of the composites were studied. Results show that the density of the composites decreases with the content of TiC increasing, and the addition of Ni significantly improves the densificationprocess by enhancing mass transfer in the bonding phase. The mechanical properties of the composites are closelyrelated with their porosity. Besides increasing the density of the composites, the addition of Ni improves the mechanical properties by other three effects: solution-strengthening the bonding phase, strengthening the FeAI-TiC interfaceand increasing ductile fracture in FeAl phase.

关键词： of in it on TiC Improving Densification and Mechanical Properties of FeAl/TiC Composites by Addition of Ni by

Processing TiAl-Based Alloy by Elemental Powder Metallurgy

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Journal of Materials Science & Technology 2000年第6期16卷 605-610页

作者： Yong LIU, Baiyun HUANG, Yuehui HE and kechao zhou (National Key Laboratory for Powder Metallurgy, Central South University of Technology, Changsha 410083, China) [Manuscript received July 31, 1999, in revised form November 19, 1999] Natl. Key Lab. for Powder Metallurgy Central South Univ. of Technol. Changsha 410083 China

TiAI-based alloys with various compositions (including Ti-48Al, Ti-47Al-2Cr-2Nb, Ti-47Al-2Cr-2Nb-0.2B and Ti-47Al-3Cr, in mole fraction) had been prepared by elemental powder metallurgy (EPM). The results have shown that the density of the prepared Ti-48AI alloy increases with increasing hot pressing temperature up to 1300℃. The Ti-48AI alloy microstructure mainly consisted of island-like Ti3Al phase and TiAl matrix at hot pressing temperature below 1300℃, however, coarse α2/γ lamellar colonies and γ grains appeared at 1400℃. It has also indicated that the additions of elemental Cr and B can refine the alloy microstructure. The main microstructural inhomogeneity in EPM TiAI-based alloys was the island-like α2 phase or the aggregate of α2/γ lamellar colony, and such island-like structure will be inherited during subsequent heat treatment in (α＋γ) field. Only after heat treatment in a field would this structure be eliminated. The mechanical properties of EPM TiAl-based alloys with various compositions were tested, and the effect of alloy elements on the mechanical properties was closely related to that of alloy elements on the alloy microstructures. Based on the above results, TiAI-based alloy exhaust valves were fabricated by elemental powder metallurgy and diffusion joining. The automobile engine test had demonstrated that the performance of the manufactured valves was very promising for engine service.

关键词： TiAl Processing TiAl-Based Alloy by Elemental Powder Metallurgy

Microstructure and mechanical properties of in-situ oxide-dispersion-strengthened NiCrFeY alloy produced by laser powder bed fusion

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Advanced Powder Materials

Advanced Powder Materials 2022年第4期1卷 88-98页

作者： Ruifeng Xu Zhaowen Geng Yiyou Wu Chao Chen Mang Ni Dan Li Taomei Zhang Hongtao Huang Feng Liu Ruidi Li kechao zhou State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Sino-French Institute of Nuclear Energy and Technology Sun Yat-sen UniversityZhuhai 519082China Shenzhen Research Institute Central South UniversityShenzhen 518057China

Oxide dispersion strengthened(ODS)superalloys are widely used in aerospace and nuclear reactors due to their exceptional creep strength and fatigue crack resistance at elevated *** this work,an ODS NiCrFeY alloy for high temperature applications was fabricated by laser powder bed fusion(L-PBF).The microstructure and mechanical properties at room and elevated temperature of the L-PBF processed ODS NiCrFeY alloy were *** was demonstrated that equiaxed grains with large fraction of low angle grain boundaries and cellular structures with high density of dislocations were obtained in the as-built *** Y_(2)O_(3)nanoparticles were in-situ formed in the ODS NiCrFeY *** of the Y_(2)O_(3)nanoparticles were located at the cellular walls and pinned with a large number of *** to the strengthening effects by dispersed Y_(2)O_(3)nanoparticles and fine cellular structures,the ODS NiCrFeY alloy showed high ultimate tensile strength of 810,560 and 250MPa at room temperature,600℃ and 800℃,respectively.

关键词： alloy Microstructure creep

Robust Cross-Linked Na_(3)V_(2)(PO_(4))_(2)F_(3) Full Sodium-Ion Batteries

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Energy & Environmental Materials 2024年第1期7卷 9-20页

作者： Jinqiang Gao Ye Tian Lianshan Ni Baowei Wang Kangyu Zou Yingchang Yang Ying Wang Craig E.Banks Dou Zhang kechao zhou Huan Liu Wentao Deng Guoqiang Zou Hongshuai Hou Xiaobo Ji College of Chemistry and Chemical Engineering Central South UniversityChangsha 410083China College of Material and Chemical Engineering Tongren UniversityTongren 554300China Department of Chemistry The Chinese University of Hong KongShatinN.T.Hong Kong S.A.R.China Faculty of Science and Engineering Manchester Metropolitan UniversityManchester UK State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China School of Materials Science and Engineering Hunan Provincial Key Lab of Advanced Materials for New Energy Storage and ConversionHunan University of Science and TechnologyXiangtan 411201China School of Materials and Engineering Zhengzhou UniversityZhengzhou 450001China

Sodium-ion batteries(SIBs)have rapidly risen to the forefront of energy storage systems as a promising supplementary for Lithium-ion batteries(LIBs).Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF)as a common cathode of SIBs,features the merits of high operating voltage,small volume change and favorable specific energy ***,it suffers from poor cycling stability and rate performance induced by its low intrinsic ***,we propose an ingenious strategy targeting superior SIBs through cross-linked NVPF with multi-dimensional nanocarbon frameworks composed of amorphous carbon and carbon nanotubes(NVPF@C@CNTs).This rational design ensures favorable particle size for shortened sodium ion transmission pathway as well as improved electronic transfer network,thus leading to enhanced charge transfer kinetics and superior cycling *** from this unique structure,significantly improved electrochemical properties are obtained,including high specific capacity(126.9 mAh g^(-1)at 1 C,1 C=128 mA g^(-1))and remarkably improved long-term cycling stability with 93.9%capacity retention after 1000 cycles at 20 *** energy density of 286.8 Wh kg^(-1)can be reached for full cells with hard carbon as anode(NVPF@C@CNTs//HC).Additionally,the electrochemical performance of the full cell at high temperature is also investigated(95.3 mAh g^(-1)after 100 cycles at 1 C at 50℃).Such nanoscale dual-carbon networks engineering and thorough discussion of ion diffusion kinetics might make contributions to accelerating the process of phosphate cathodes in SIBs for large-scale energy storages.

关键词： dual-nanocarbon networks full sodium-ion battery ion transfer kinetics Na_(3)V_(2)(PO_(4))_(2)F_(3) NASICON structure

OPTIMIZATION OF ELECTRODE FINGER WIDTH IN PIEZOELECTRIC FIBER COMPOSITES

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OPTIMIZATION OF ELECTRODE FINGER WIDTH IN PIEZOELECTRIC FIBE...

原始粉料的球磨工艺对Ti/HA生物复合材料性能的影响

2013全国压电和声波理论及器件技术研讨会

作者： Haiyan CHEN Xiujuan LIN Dou ZHANG kechao zhou State Key Laboratory of Powder Metallurgy Central South University

Finite element analysis was performed on the representative volume element of piezoelectric elements with interdigitated electrodes（IDEs）.The variations of piezoelectric material properties during poling were considered in the *** numerical results of models with different piezoelectric polarization states were compared with the result given by the so called uniform field *** different optimum electrode finger widths were obtained for different models,narrower electrode finger could enhance the actuation *** models indicated the stress concentrated at the edges of the finger *** electrode finger would be beneficial for reducing the risk of material *** model with two different polarization states could be used to predict the strain and stress of PFCs with wider electrode finger to minimize the computational *** modeling approach developed in this study allowed for a better understanding on the overall effects in piezoelectric materials with IDE structures.

关键词： finite element analysis electrode finger width polarization state strain stress

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粉末冶金技术 2005年第2期23卷 116-119页

作者：刘芳周科朝刘咏中南大学粉末冶金国家重点实验室湖南长沙410083

采用不同球磨介质对Ti+30%HA配比的粉料进行高能球磨,随后于1000℃氩气气氛中热压,研究了球磨工艺对Ti/HA生物复合材料性能的影响。结果表明:随着球磨时间的延长,复合材料的致密度略有下降,硬度上升。热压后,Ti基体形成连通的网络,HA弥... 详细信息

采用不同球磨介质对Ti+30%HA配比的粉料进行高能球磨,随后于1000℃氩气气氛中热压,研究了球磨工艺对Ti/HA生物复合材料性能的影响。结果表明:随着球磨时间的延长,复合材料的致密度略有下降,硬度上升。热压后,Ti基体形成连通的网络,HA弥散分布其中。干磨工艺条件下,球磨时间越长,显微组织越细;湿磨工艺条件下,较短的球磨时间,即可达到较好的细化弥散效果。因此,采用高能球磨,可使Ti/HA生物复合材料在较低的温度下致密化,同时,湿磨介质的存在,有利于在短时间内得到力学性能和生物活性都较好的Ti/HA生物复合材料。

关键词：复合材料性能球磨工艺粉料生物复合材料原始球磨时间高能球磨工艺条件球磨介质弥散分布显微组织生物活性力学性能 HA Ti 致密度致密化热压气氛氩气

HA/HDPE多尺度生物复合材料微观强韧化机制

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复合材料学报 2010年第3期27卷 67-72页

作者：黄苏萍周科朝中南大学粉末冶金国家重点实验室长沙410083 中南大学湘雅三医院长沙410013

通过电镜分析及理论推导对羟基磷灰石(Hydroxyapatite,HA)/高密度聚乙烯(High density polyethylene,HDPE)复合材料界面粘结状态、HA颗粒对裂纹扩展的钝化、钉扎作用、复合纤维对体系分子热激活能的影响及复合纤维的能量吸收机制与增强... 详细信息

通过电镜分析及理论推导对羟基磷灰石(Hydroxyapatite,HA)/高密度聚乙烯(High density polyethylene,HDPE)复合材料界面粘结状态、HA颗粒对裂纹扩展的钝化、钉扎作用、复合纤维对体系分子热激活能的影响及复合纤维的能量吸收机制与增强增韧等进行了深入研究。结果表明:HA/HDPE复合材料通过纳米HA颗粒与HA/HDPE复合纤维在不同尺度上协同作用达到增强增韧的效果。即在纳米尺度,纳米HA颗粒的均匀分散和高的HA/HDPE界面结合强度显著提高了HDPE的结晶度,细化了HDPE晶粒尺寸,并在HA颗粒表面形成取向结晶层,从而使材料在断裂过程中通过HDPE取向结晶层的基体形变和HA脱粘过程对微裂纹起钝化和钉扎作用,并扩大能量耗散的区域,以阻滞微孔隙和银纹的长大和破断,抑制大裂纹的早期形成。在微米尺度,由于HA/HDPE复合纤维的定向排列,使体系的活化体积显著降低,大大增加了材料的断裂热激活能,从而显著提高材料的强度。另一方面,复合纤维在应力作用过程中通过纤维断裂、纤维拔出、裂纹偏转机制使材料在形变与破坏过程中耗散更多的能量,从而显著提高材料的强度和韧性。

关键词： HA/HDPE复合材料多尺度结构强韧化机制

Effect of WC Addition on The Microstructure and Mechanical Properties of TiN-based Cermets

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Effect of WC Addition on The Microstructure and Mechanical P...

热处理对挤压铸造n-SiC_p/AZ91D镁基复合材料组织和力学性能的影响

第十八届中国科协年会——分7 全国稀有及贵金属材料学术交流会

作者： Wenmiao ZENG Xueping GAN Zhiyou LI kechao zhou State Key Laboratory of Powder Metallurgy Central South University

The application of TiN, up to now, is strongly limited to the coating material for various cutting tools and ornaments, while the synthesis of adequate bulk titanium nitride materials would be desirable for several applications to better meet different demands. In this paper, the TiN-WC-Ni-Co system cermets with nearly full density were successfully fabricated by conventional vacuum sintering with the addition of WC and were systematically investigated by scanning electron microscopy, X-ray diffraction and mechanical properties tests. Effect of WC addition on the microstructure and mechanical properties of TiN-based cermets was studied in this work. The results show that WC significantly helps to improve the wettability between TiN and Ni/Co through the formation of typical core-rim structure, which is rather beneficial to obtain the cermets with full densification and homogeneous microstructure. As the addition of WC content increases from 0 wt% to 25 wt%, the microstructure has an obvious trend to become denser and finer and the mechanical properties of the TiN-based cermets are enhanced greatly. When the WC content is 20 wt%, the relative density, transverse rupture strength, fracture toughness and Rockwell hardness of the cermets reach 99.5%, 1235 MPa, 12.6 MPa m and 88.2, respectively.

关键词： Ti N-based cermets WC Mechanical properties Microstructure

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稀有金属材料与工程 2015年第6期44卷 463-468页

作者：张从阳冯荣宇李文珍清华大学北京100084

采用金相、X射线衍射、扫描电镜(SEM)、拉伸试验等方法分析和测试了挤压铸造纳米Si C颗粒增强AZ91D镁基复合材料在铸态(F)、固溶态(T4)和人工时效态(T6)下的组织和力学性能。结果表明,固溶处理可使n-Si Cp/AZ91D铸态组织中的β-Mg17Al1... 详细信息

采用金相、X射线衍射、扫描电镜(SEM)、拉伸试验等方法分析和测试了挤压铸造纳米Si C颗粒增强AZ91D镁基复合材料在铸态(F)、固溶态(T4)和人工时效态(T6)下的组织和力学性能。结果表明,固溶处理可使n-Si Cp/AZ91D铸态组织中的β-Mg17Al12共晶相溶入到基体中,形成单一的过饱和α-Mg固溶体,合金抗拉强度和伸长率均有大幅提高,分别达到265 MPa和13.7%;经时效处理后,复合材料的抗拉强度和屈服强度进一步提高,分别为275,145 MPa;SEM结果显示,β-Mg17Al12相主要以连续析出/非连续析出方式分别在晶内及晶界上析出,特别是纳米Si C颗粒分布对二次析出相β-Mg17Al12的形貌、尺寸、分布有一定的影响,使二次析出相变得细小和弥散分布,从而充分发挥了二次析出相的沉淀强化作用;最后对n-Si Cp/AZ91D复合材料不同热处理条件下的断口形貌进行了SEM观察,并且对其断裂方式进行了分析和讨论。

关键词：镁基纳米复合材料挤压铸造热处理微观组织力学性能