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Influence of hot-rolling on the microstructure and mechanical properties of a near β-type Ti-5.2Mo-4.8Al-2.5Zr-1.7Cr alloy

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Progress in Natural Science:Materials International 2022年第4期32卷 504-509页

作者： xinjie zhu Qunbo Fan Guxin Zhou Duoduo Wang Chinese Weapons Science Academy Ningbo Branch National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and Engineering Beijing Institute of Technology

In this work, the 90° clock rolling and the uni-directionally rolling processes at high temperature were carried out on the near β-type Ti-5.2Mo-4.8Al-2.5Zr-1.7Cr titanium alloy cutting from an ingot, respectively. The corresponding microstructures were quantitatively characterized, and its effect on the dynamic mechanical properties and fracture mechanism were emphatically investigated. It was found that after 90° clock rolling, the microstructure composed of equiaxed primary α phase(αp) with an average size of about 2 μm and the β transformed regions containing the acicular secondary α phase(αs) with an average thickness of about 50 nm and the separated β phase was obtained. However, in the uni-directionally rolled titanium alloy, no acicular αswas observed, and the corresponding microstructure consisted elongated lamellar α phase(average thickness: about 1.3 μm), few equiaxed α phase(average grain size: about 300 nm) and the inlaid β phase. The microstructural difference of the hot-rolled titanium alloys was closely related to the deformation process. Moreover, a great number of αpand αsin the 90° clock rolled titanium alloy effectively enhanced the strength, and the dynamic compressive strength reached to 1730 MPa. Furthermore, equiaxed αpwas conducive to the homogeneous deformation, which counteracted the localized deformation caused by acicular αsto a certain extent and made the 90°clock rolled titanium alloy exhibit an acceptable critical fracture strain of about 10.5%. Moreover, the fracture microstructures showed that the main failure mode of the 90°clock rolled and the uni-directionally rolled titanium alloy were ductile fracture and brittle fracture, respectively.

关键词： 90° clock rolling Microstructure Mechanical properties Titanium alloy

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Heat Transfer Prediction of Supercritical Carbon Dioxide in Vertical Tube Based on Artificial Neural Networks

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Journal of Thermal Science 2021年第5期30卷 1751-1767页

作者： zhu Bingguo zhu xinjie XIE Jian XU Jinliang LIU Huan Key Laboratory of Power Station Energy Transfer Conversion and System North China Electric Power UniversityMinistry of EducationBeijing102206China School of Mechanical&Electronical Engineering Lanzhou University of TechnologyLanzhou730050China Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power UniversityBeijing102206China

Accurate prediction of supercritical CO_(2)(scCO_(2))heat transfer is important for heat exchanger design and safe operation of scCO_(2)power *** main prediction method is empirical *** paper demonstrates an alternative way by artificial neural networks(ANN)model with two hidden *** assess widely cited correlations and newly developed ANN model,scCO_(2)heat transfer experiment in vertical tube with pressure up to 20.8 MPa was performed to extend experiment database,which includes 2674 *** with empirical correlations,the ANN model is promising for following advantages:(1)ANN model has much better prediction *** mean relative error,mean absolute relative error and the root-mean-square relative error between predicted and measured wall temperatures are eA=0.38%,eR=4.88%and eS=7.29%,respectively.(2)ANN model performs faster computation speed.(3)ANN model can accurately and speedily predict scCO_(2)heat transfer performance for both normal heat transfer and heat transfer deterioration *** trained ANN program is provided with this paper,which is a useful tool and can be directly applied in engineering of scCO_(2)heat transfer.

关键词： supercritical CO_(2) heat transfer prediction ANN model correlations

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Microstructure evolution and mechanical properties of a hot-rolled Ti alloy

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Progress in Natural Science:Materials International 2021年第1期31卷 105-112页

作者： xinjie zhu Qunbo Fan Xin Liu Hong Yu Duoduo Wang School of Materials Science and Engineering Beijing Institute of Technology National Key Laboratory of Science and Technology on Materials Under Shock and Impact Beijing Institute of Technology Beijing Institute of Technology Chongqing Innovation Center

The microstructure evolution and mechanical properties of a hot-rolled Ti-5.1 Al-2.5 Cr-0.5 Fe-4.5 Mo-1.1 Sn-1.8 Zr-2.9 Zn titanium alloy sheet along the thickness direction were *** results indicated that the hotrolled titanium alloy sheet presented different microstructures along the thickness direction owing to the uneven distribution of stress and temperature during the hot *** grains in central region underwent a larger deformation,leading to relative complete grain fragmentation and the formation of fine *** the air cooling process followed by hot rolling,the fraction of a phase precipitated in the central region was lower than that in the regions near the surface of the *** hot rolling process,more deformation energy transformed to thermal energy and lower cooling rate in the central region promoted the α→β phase transformation,resulting in the increasing of the dynamic recrystallization in the β *** contrast,the dynamic recrystallization for a phase *** {0001}αand {001}βtextures were observed,and these textures were markedly strengthened with the increasing distance from the central *** to the softening induced by dynamic recrystallization and the strengthening by concentrated dislocations,the surface of the sheet exhibits highest yield strength and lowest elongation.

关键词： Titanium alloys Microstructure evolution Mechanical properties Hot rolling

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Empirical prediction of hydraulic aperture of 2D rough fractures:a systematic numerical study

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Frontiers of Earth Science 2024年第3期18卷 579-597页

作者： Xiaolin WANG Shuchen LI Richeng LIU xinjie zhu Minghui HU State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China

This study aims to propose an empirical prediction model of hydraulic aperture of 2D rough fractures through numerical simulations by considering the influences of fracture length,average mechanical aperture,minimum mechanical aperture,joint roughness coefficient(JRC)and hydraulic *** generate 600 numerical models using successive random additions(SRA)algorithm and for each model,seven hydraulic gradients spanning from 2.5×10^(-7)to 1 are considered to fully cover both linear and nonlinear flow *** a result,a total of 4200 fluid flow cases are simulated,which can provide sufficient data for the prediction of hydraulic *** results show that as the ratio of average mechanical aperture to fracture length increases from 0.01 to 0.2,the hydraulic aperture increases following logarithm *** the hydraulic gradient increases from 2.5×10^(-7)to 1,the hydraulic aperture decreases following logarithm *** a relatively low hydraulic gradient(i.e.,5×10^(-7))is applied between the inlet and the outlet boundaries,the streamlines are of parallel distribution within the ***,when a relatively large hydraulic gradient(i.e.,0.5)is applied between the inlet and the outlet boundaries,the streamlines are disturbed and a number of eddies are *** hydraulic aperture predicted using the proposed empirical functions agree well with the calculated results and is more reliable than those available in the preceding *** practice,the hydraulic aperture can be calculated as a first-order estimation using the proposed prediction model when the associated parameters are given.

关键词： fluid flow rough fracture surface mechanical aperture hydraulic aperture predictive model

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Multi-scale crystal plasticity finite element simulations of the microstructural evolution and formation mechanism of adiabatic shear bands in dual-phase Ti20C alloy under complex dynamic loading

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Journal of Materials Science & Technology 2020年第24期59卷 138-148页

作者： Yu Zhou Qunbo Fan Xin Liu Duoduo Wang xinjie zhu Kai Chen School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China National Key Laboratory of Science and Technology on Materials Under Shock and Impact Beijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401135China

A dynamic compression test was performed on α+β dual-phase titanium alloy Ti20C using a split Hopkinson pressure *** formation of adiabatic shear bands generated during the compression process was studied by combining the proposed multi-scale crystal plasticity finite element method with experimental *** complex local micro region load was progressively extracted from the simulation results of a macro model and applied to an established three-dimensional multi-grain microstructure ***,the evolution histories of the grain shape,size,and orientation inside the adiabatic shear band were quantitatively *** results corresponded closely to the experimental results obtained via transmission electron microscopy and precession electron ***,by calculating the grain rotation and temperature rise inside the adiabatic shear band,the microstructural softening and thermal softening effects of typical heavily-deformed α grains were successfully *** results revealed that the microstructural softening stress was triggered and then stabilized(in general)at a relatively high *** indicated that the mechanical strength was lowered mainly by the grain orientation evolution or dynamic recrystallization occurring during early plastic ***,thermal softening increased linearly and became the main softening ***,in the final stage,the thermal softening stress accounted for 78.4% of the total softening stress due to the sharp temperature increase,which inevitably leads to the stress collapse and potential failure of the alloy.

关键词： Titanium alloy Adiabatic shear band Multi-scale crystal plastic finite element method(CPFEM) Orientation evolution Softening mechanism

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Influence of Temperature on Stacking Fault Energy and Creep Mechanism of a Single Crystal Nickel-based Superalloy

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Journal of Materials Science & Technology 2016年第8期32卷 790-798页

作者： Sugui Tian xinjie zhu Jing Wu Huichen Yu Delong Shu Benjiang Qian Shenyang University of Technology Shenyang 110870 China Aviation Key Laboratory of Science and Technology on Materials Testing and Evaluation Science and Technology on Advanced High TemperatureStructural Materials Laboratory Beijing Institute of Aeronautical Materials Beijing 100095 China

The influence of temperatures on the stacking fault energies and deformation mechanism of a Re- containing single crystal nickel-based superalloy during creep at elevated temperatures was investigated by means of calculating the stacking fault energy of alloy, measuring creep properties and performing contrast analysis of dislocation configuration. The results show that the alloy at 760 ℃ possesses lower stacking fault energy, and the stacking fault of alloy increases with increasing temperature. The defor- mation mechanism of alloy during creep at 760 ℃ is 7＇ phase sheared by 〈110〉 super-dislocations, which may be decomposed to form the configuration of Shockley partials plus super-lattice intrinsic stacking fault, while the deformation mechanism of alloy during creep at 1070 ℃ is the screw or edge super- dislocations shearing into the rafted 7＇ phase. But during creep at 7（50 and 980 ℃, some super- dislocations shearing into 7＇ phase may cross-slip from the {111} to {100} planes to form the K-W locks with non-plane core structure, which may restrain the dislocations slipping to enhance the creep resis- tance of alloy at high temperature. The interaction between the Re and other elements may decrease the diffusion rate of atoms to improve the microstructure stability, which is thought to be the main reason why the K-W locks are to be kept in the Re-containing superalloy during creep at 980 ℃.

关键词： Single crystal nickel-based superalloy Stacking fault energy Creep Contrast analysis Deformation mechanism

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Dynamics and genetic regulation of macronutrient concentrations during grain development in maize

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Journal of Integrative Agriculture 2024年第3期23卷 781-794页

作者： Pengcheng Li Shuangyi Yin Yunyun Wang Tianze zhu xinjie zhu Minggang Ji Wenye Rui Houmiao Wang Chenwu Xu Zefeng Yang Jiangsu Key Laboratory of Crop Genetics and Physiology/Key Laboratory of Plant Functional Genomics Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding/Agricultural CollegeYangzhou UniversityYangzhou 225009China Jiangsu Co-lnnovation Center for Modern Production Technology of Grain Crops Yangzhou UniversityYangzhou 225009China

Nitrogen(N), phosphorus(P), and potassium(K) are essential macronutrients that are crucial not only for maize growth and development, but also for crop yield and quality. The genetic basis of macronutrient dynamics and accumulation during grain filling in maize remains largely unknown. In this study, we evaluated grain N, P, and K concentrations in 206 recombinant inbred lines generated from a cross of DH1M and T877 at six time points after pollination. We then calculated conditional phenotypic values at different time intervals to explore the dynamic characteristics of the N, P, and K concentrations. Abundant phenotypic variations were observed in the concentrations and net changes of these nutrients. Unconditional quantitative trait locus(QTL) mapping revealed 41 non-redundant QTLs, including 17, 16, and 14 for the N, P, and K concentrations, respectively. Conditional QTL mapping uncovered 39 non-redundant QTLs related to net changes in the N, P, and K concentrations. By combining QTL, gene expression, co-expression analysis, and comparative genomic data, we identified 44, 36, and 44 candidate genes for the N, P, and K concentrations, respectively, including GRMZM2G371058 encoding a Doftype zinc finger DNA-binding family protein, which was associated with the N concentration, and GRMZM2G113967encoding a CBL-interacting protein kinase, which was related to the K concentration. The results deepen our understanding of the genetic factors controlling N, P, and K accumulation during maize grain development and provide valuable genes for the genetic improvement of nutrient concentrations in maize.

关键词： maize nutrient concentration unconditional QTL mapping conditional QTL mapping dynamic trait

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Deformation mechanism of fine structure and its quantitative relationship with quasi-static mechanical properties in near β-type Ti-4.5Mo-5.1Al-1.8Zr-1.1Sn-2.5Cr-2.9Zn alloy

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Progress in Natural Science:Materials International 2021年第5期31卷 742-748页

作者： xinjie zhu Qunbo Fan Duoduo Wang Haichao Gong Yu Gao Hong Yu Xingwang Cheng Zhiming Zhou Liu Yang National Key Laboratory of Science and Technology on Materials Under Shock and Impact School of Materials Science and Engineering Beijing Institute of Technology Beijing Institute of Technology Chongqing Innovation Center School of Materials Science and Engineering Chongqing University of Technology Chengdu Advanced Metal Materials Industrial Technology Research Institute Co.Ltd.

The deformation mechanism of the fine structure composed of primary α phase(αp) and acicular secondary αphase(αs) on quasi-static mechanical properties is still not very clear. The main controversy is focused on the role of αpin the mechanical behavior. In this paper, the microstructure of the heat-treated near β-type Ti-4.5 Mo-5.1 Al-1.8 Zr-1.1 Sn-2.5 Cr-2.9 Zn alloy after tensile tests was observed by transmission electron microscopy(TEM). And the results showed that in the slight deformation region the dislocations were accumulated at the intersection ofαpand β matrix separated by αs, while only a few dislocations nucleated in β matrix. In the severe deformation region, a large quantity of dislocations in both αpand β matrix were observed. It can be inferred that αpdeformed firstly and then activated the deformation of β matrix, that is, the thickness of αpand the inter-particle spacing ofαsplayed a dominant role in the deformation process. The quantitative relationship between the yield strength and the microstructure parameters is consistent with this inference. By adjusting the solution treatment parameters and the subsequent aging treatment, three fine structures were obtained, and the corresponding mechanical properties were determined. Furthermore, the yield strength can be described by the mathematical model σy= 756.4 + 135.6/hp1/2+32.2/ds1/2, where hpand dsare the thickness of αpand the inter-particle spacing of αs,respectively.

关键词： Deformation mechanism Fine structure Quantitative relationship Titanium alloy

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Combining QTL Mapping and Multi-Omics Identify Candidate Genes for Nutritional Quality Traits during Grain Filling Stage in Maize

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Phyton-International Journal of Experimental Botany 2024年第7期93卷 1441-1453页

作者： Pengcheng Li Tianze zhu Yunyun Wang Shuangyi Yin xinjie zhu Minggang Ji Wenye Rui Houmiao Wang Zefeng Yang Chenwu Xu Jiangsu Key Laboratory of Crop Genetics and Physiology Key Laboratory of Plant Functional Genomics of the Ministry of EducationJiangsu Key Laboratory of Crop Genomics and Molecular BreedingAgricultural College of Yangzhou UniversityYangzhou225009China Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops Yangzhou UniversityYangzhou225009China

The nutritional composition and overall quality of maize kernels are largely determined by the key chemical com-ponents:protein,oil,and ***,the genetic basis underlying these nutritional quality traits during grainﬁlling remains poorly *** this study,the concentrations of protein,oil,and starch were studied in 204 recombinant inbred lines resulting from a cross between DH1M and T877 at four different stages *** the traits exhibited considerable phenotypic *** the grain-ﬁlling stage,the levels of protein and starch content generally increased,whereas oil content decreased,with signiﬁcant changes observed between 30 and 40 days after *** trait locus(QTL)mapping was conducted and a total of 32 QTLs,comprising 14,12,and 6 QTLs for grain protein,oil,and starch content were detected,*** QTLs were consistently detectable across different time *** integrating QTL analysis,glo-bal gene expression proﬁling,and comparative genomics,we identiﬁed 157,86,and 54 differentially expressed genes harboring nonsynonymous substitutions between the parental lines for grain protein,oil,and starch con-tent,*** gene function annotation prioritized 15 candidate genes potentially involved in reg-ulating grain quality traits,including those encoding transcription factors(NAC,MADS-box,bZIP,and MYB),cell wall invertase,cellulose-synthase-like protein,cell division cycle protein,trehalase,auxin-responsive factor,and phloem protein *** study offers signiﬁcant insights into the genetic architecture of maize kernel nutritional quality and identiﬁes promising QTLs and candidate genes,which are crucial for the genetic enhance-ment of these traits in maize breeding programs.

关键词： Maize protein oil starch QTL mapping candidate genes

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Present Situation and its Causes of College English Learning and Practice Environment in China

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International English Education Research 2015年第8期 15-19页

作者： zhu xinjie Zhengzhou University of Science and Technology No. 1 Xueyuan Road Erqi District Zhengzhou City Henan Province China 450064

Language learning must be conducted on the basis of acquisition, and the acquisition needs a certain environment as the material guarantee for the implementation of the learning activities. In China, English teaching lacks an advantageous learning environment as a Foreign Language （EFL） Teaching, which is one of main factors that more time is spent on the teaching but efficiency is not improved correspondingly. Therefore, we should attach more importance to the present situation and its causes. In this essay, present Situation is analyzed through the practical research, and the causes are explored to help to improve the efficiency of foreign language learning.

关键词： English teaching Learning and practice environment Present Situation and its causes

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