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Study on the formation mechanism of α lamellae in a near β titanium alloy

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Progress in Natural Science:Materials International 2016年第4期26卷 385-390页

作者： Bin Tang Hongchao Kou Xue Zhang Puyi Gao jinshan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical University

In order to obtain more insight in the two existing mechanisms on the nucleation, i.e., sympathetic nucleation and interface instability nucleation, of α lamellae in the near β Ti alloys, the micro-texture ofα lamellae in Ti-7Mo-3Nb-3Cr-3Al has been investigated by using electron backscatter diffraction（EBSD）.The results show that the αWGBlamellae can not only grow up from αGBgrains by inheriting the orientations but also sympathetically nucleate at the αGB/β interface during the slow cooling process. These observations provide the first direct experimental evidence that the formation mode of α lamellae in Ti-7333 alloy consists of sympathetic nucleation and interface instability nucleation. Based on the present results together with some previous studies on α phase transformation in Ti-based alloys the influence of β-stabilizers parameter on the change of formation mechanism of α lamellae was discussed.

关键词： Near β Ti alloys α Lamellae Sympathetic nucleation Interface instability nucleation Phase transformation

Research on KOH/La-Ba-Al_2O_3 catalysts for biodiesel production via transesterification from microalgae oil

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Journal of Natural Gas Chemistry 2012年第6期21卷 774-779页

作者： Xiaoyu Zhang Qing Ma Bibo Cheng Jun Wang jinshan Li Fude Nie Institute of Chemical Materials China Academy of Engineering Physics(CAEP)Mianyang 621900SichuanChina

Alumina supports modified by lanthanum （La） and barium （Ba） were prepared by peptization. Catalysts with different KOH contents supported on modified alumina were prepared by impregnation method. Various techniques, including N2 adsorption-desorption （Brunauer-Emmet-Teller method, BET）, X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and fourier transform infrared absorption spectroscopy （FT-IR）. Catalytic activity for microalgae oil conversion to methyl ester via transesterification was evaluated and analyzed by GC-MS and GC. BET results showed that the support possessed high specific surface area, suitable pore volume and pore size distribution. Activity results indicated that the catalyst with 25 wt% KOH showed the best activity for microalgae oil conversion. XRD and SEM results revealed that Al-O-K compound was the active phase for microalgae oil conversion. The agglomeration and changing of pore structure should be the main reasons for the catalyst deactivation when KOH content was higher than 30 wt%.

关键词： biodiesel microalgae oil La2O3 BaO solid catalyst

Microstructure and texture evolution of a near β titanium alloy Ti-7333 during continuous cooling hot deformation

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Progress in Natural Science:Materials International 2019年第1期29卷 50-56页

作者： Jiahao Chen jinshan Li Bin Tang Yi Chen Hongchao Kou State Key Laboratory of Solidification Processing Northwestern Polytechnical University Key Construction Laboratory of Green Forming and Equipment from Jiangsu Province Jiangsu University of Technology

The microstructure and texture evolution during continuous cooling hot deformation(CCHD) in a near β titanium alloy, named Ti-7Mo-3Nb-3Cr-3Al(Ti-7333), were investigated by using the electron backscattered diffraction(EBSD). The results indicate that the precipitation of secondary α phase was restricted by CCHD, and the morphology of primary α phase nearly had no change with the deformation and temperature drop. In contrast, βphase underwent more deformation and the grains tended to refine. This may be due to the dynamic recrystallization(DRX) of β phase, including continuous dynamic recrystallization(CDRX) and discontinuous dynamic recrystallization(DDRX). In addition, the textures of {110} , {225} and{115} transformed to {100} and {001} during CCHD. Among these, the η-fiber component of {001} was the dominant deformation texture in the deformed Ti-7333 alloy. Finally,continuous cooling has an important effect on the work hardening and softening during CCHD, contributing to the different flow behaviors at different cooling rates.

关键词： Near β titanium alloy Thermo-mechanical processing Texture Dynamic recrystallization

High Quality Audio Object Coding Framework Based on Non-Negative Matrix Factorization

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China Communications 2017年第9期14卷 32-41页

作者： Tingzhao Wu Ruimin Hu Xiaochen Wang Shanfa Ke jinshan Wang National Engineering Research Center for Multimedia Software School of Computer ScienceWuhan University Hubei Key Laboratory of Multimedia and Network Communication Engineering Wuhan University Collaborative Innovation Center of Geospatial Technology

Object-based audio coding is the main technique of audio scene coding. It can effectively reconstruct each object trajectory, besides provide sufficient flexibility for personalized audio scene reconstruction. So more and more attentions have been paid to the object-based audio coding. However, existing object-based techniques have poor sound quality because of low parameter frequency domain resolution. In order to achieve high quality audio object coding, we propose a new coding framework with introducing the non-negative matrix factorization(NMF) method. We extract object parameters with high resolution to improve sound quality, and apply NMF method to parameter coding to reduce the high bitrate caused by high resolution. And the experimental results have shown that the proposed framework can improve the coding quality by 25%, so it can provide a better solution to encode audio scene in a more flexible and higher quality way.

关键词： object-based audio coding non-negative matrix factorization audio scenecoding

Mechanical characterization and strain-rate sensitivity measurement of Ti-7333 alloy based on nanoindentation and crystal plasticity modeling

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Progress in Natural Science:Materials International 2018年第6期28卷 718-723页

作者： Mengqi Zhang jinshan Li Bin Tang Hongchao Kou Jiangkun Fan State Key Laboratory of Solidification Processing Northwestern Polytechnical University

The relationship between crystal orientations and meso-mechanical properties of β phase Ti-7333 titanium was investigated through the combination of nanoindentation experiments and simulation. The crystal plasticity finite element（CPFE） model for nanoindentation of single body-centered cubic crystal was established based on the experimental data. And the crystal plasticity constitutive law was implemented to simulate the nanoindentation process, obtaining satisfied results with an acceptable error. From the simulated pileup morphology patterns with different crystal orientations, it was found that the β phase experienced a symmetrical and orientation-related deformation process. Meanwhile, the strain-rate sensitivity（SRS） of β phase was investigated through nanoindentation tests based on continuous stiffness measurement（CSM） under different strain rates,varying between 0.2, 0.05 and 0.01 s-1. Two grains with different orientations exhibited similar SRS exponents,m, calculated from the experimental results.

关键词： Nanoindentation Crystal plasticity Rate sensitivity Pileup

Optimisation of superplastic processing parameters for (Cu_(43)Zr_(48)Al_9)_(98)Y_2 bulk metallic glasses

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Journal of Rare Earths 2019年第1期37卷 95-100,M0005页

作者： Bing Li Xuanxuan Xu Hucheng Zhang Ke Yang Xinhui Fan jinshan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical University Shaanxi Key Laboratory for Photoelectric Functional Materials and Devices Xi'an Technological University Shanxi Jiangyang Chemical Co. Ltd.

In this study,hot compression tests of (Cu_(43)Zr_(48)Al_9)_(98)Y_2 bulk metallic glasses (BMGs) were performed,and their micro structure and thermal properties after the deformation were studied to explore the appropriate range of their optimum processing parameters. The experimental results show that the superplastic deformation of (Cu_(43)Zr_(48)Al_9)_(98)Y_2 bulk metallic glasses depends mainly on the temperature and strain rate. It is suitable for superplastic processing when the alloys are in the state of Newtonian flow and do not crystallise. The appropriate processing parameters of (Cu_(43)Zr_(48)Al_9)_(98)Y_2 BMGs are the temperatures and strain rates, which are below the "dividing line". And when the temperature is above733 K, the strain rate must be>1×10^(-3) s^(-1).

关键词： Bulk metallic glasses Superplastic Flow behaviour Crystallisation behaviour Rare earths

Hot Deformation and Subsequent Annealing on the Microstructure and Hardness of an Al0.3CoCrFeNi High-entropy Alloy

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Acta Metallurgica Sinica(English Letters) 2021年第11期34卷 1527-1536页

作者： Jun Wang Hongchao Li Haoxue Yang Yu Zhang William Yi Wang jinshan Li State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China

The infl uence of simple thermomechanical processing such as hot deformation and heat treatment on the microstructure and hardness of an Al0.3CoCrFeNi high-entropy alloy has been *** show that the relatively high deformation temperature can induce discontinuous dynamic recrystallization with fine grains initially nucleating at the elongated grain *** transition from partial recrystallization to fully recrystallization,as well as the precipitation behavior after annealing,has been described in *** bcc precipitation and completely recrystallized grains can be observed after annealing at 1000℃.Based on detailed microstructure analysis,the decrease in hardness value is shown to be related to both dynamic recrystallization and dynamic recovery which lead to softening.

关键词： High-entropy alloy Hot deformation Annealing Microstructure Recrystallization

Effect of Ce-rich rare earth on microstructure and mechanical properties of Mg-10Zn-5Al-0.1Sb magnesium alloy

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China Foundry 2012年第2期9卷 131-135页

作者： You Zhiyong Zhang Zhaoguang Zhang jinshan Wei Yinghui College of Materials Science and Engineering Taiyuan Universioof TechnologyTaivuan Shanxi 030024China

To improve the comprehensive mechanical properties of Mg-10Zn-5Al-0.1Sb magnesium alloy, different amount of Ce-rich rare earth （RE） was added to the alloy, and the effect of RE addition on the microstructure and mechanical properties of Mg-10Zn-5Al-0.1Sb alloy was investigated by means of Brinell hardness measurement, scanning electron microscopy （SEM）, energy dispersive spectroscope （EDS） and X-ray diffraction （XRD）. The results show that an appropriate amount of Ce-rich rare earth addition can make the AI4Ce phase particles and CeSb phase disperse more evenly in the alloy. These phases refine the alloy＇s matrix and make the secondary phases [τ-Mg32（AI,Zn）49 phase and φ-Al2MgsZn2 phase] finer and more dispersive, therefore significantly improve the mechanical properties of the Mg-10Zn-5AI-0,1Sb alloy. When the RE addition is 1.0 wt.%, the tensile strengths of the alloy both at room temperature and 150℃ reach the maximum values while the impact toughness is slightly lower than that of the matrix alloy. The hardness increases with the increase of RE addition.

关键词： ZA105 microstructure mechanical properties Ce-rich rare earth Ce4Al

新型冠状窦造影球囊导管在心脏再同步治疗起搏器植入术中的应用

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中国心血管杂志 2022年第1期27卷 28-31页

作者：段江波何金山王龙李鼎昃峰吴寸草周旭杨丹丹周晶亮李学斌北京大学人民医院心内科 100044

目的评估新型冠状窦造影球囊导管在心脏再同步治疗(CRT)起搏器植入术中应用的有效性和安全性。方法连续入选2019年1月1日至12月1日于北京大学人民医院心内科就诊的具有CRT起搏器(包括CRT-P和CRT-D)植入指征的患者25例,排除既往植入失败... 详细信息

目的评估新型冠状窦造影球囊导管在心脏再同步治疗(CRT)起搏器植入术中应用的有效性和安全性。方法连续入选2019年1月1日至12月1日于北京大学人民医院心内科就诊的具有CRT起搏器(包括CRT-P和CRT-D)植入指征的患者25例,排除既往植入失败和拒绝签署知情同意书者5例,符合入选标准的20例患者应用新型冠状窦造影球囊导管进行CRT植入,统计这些患者CRT植入时间、左室电极植入时间、冠状窦夹层和心包积液发生率,计算CRT植入成功率。结果20例患者中,男性12例,平均年龄(62.3±4.5)岁,缺血性心肌病6例,平均纽约心脏病协会(NYHA)心功能分级(2.5±0.8)级,平均左室舒张末期内径(52.6±3.3)mm,平均射血分数38.0%±5.0%,平均左室电极植入时间(12.3±2.4)min,平均手术时间(54.6±6.2)min,CRT总体植入成功率100%。全部患者均无膈肌刺激,均未发生冠状窦夹层,术中无患者发生心脏压塞,术后复查超声心动图均无新发心包积液。结论新型冠状窦造影球囊导管能够在较短时间内完成CRT左室电极植入,与既往植入方法相比,可减少术中X线曝光时间,降低冠状静脉夹层发生率,提高CRT植入成功率。

关键词：冠状窦造影导管心脏再同步治疗除颤器,植入型电极,植入冠状窦夹层心脏压塞成功率