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Effects of friction stir processing and nano-hydroxyapatite on the microstructure,hardness,degradation rate and in-vitro bioactivity of WE43 alloy for biomedical applications

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Journal of Magnesium and Alloys 2024年第1期12卷 209-224页

作者： Bo Wu Farazila Yusof fuguo li Huan Miao A.R.Bushroa Mohd Ridha Bin Muhamad Irfan Anjum Badruddin Mahmoud Z.Ibrahim Department of Mechanical Engineering Faculty of EngineeringUniversiti MalayaKuala Lumpur 50603Malaysia Centre of Advanced Manufacturing and Material Processing(AMMP Centre) Universiti MalayaKuala Lumpur 50603Malaysia Center of Foundation studies in Science Universiti MalayaKuala Lumpur 50603Malaysia State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Mechanical Engineering Department College of EngineeringKing Khalid UniversityAbha 61421Saudi Arabia Design and Production Engineering Faculty of EngineeringAin Shams UniversityCairo 11517Egypt

Nowadays,magnesium alloys are emerging in biomedical implants for their similar properties to natural ***,the rapid degradation of magnesium alloys in biological media hinders successful *** of microstructure,as well as reinforcement particles can significantly improve the degradation *** this work,multi-pass friction stir processing(FSP)was proposed to synthesize WE43/nano-hydroxyapatite(n HA)surface composite,the microstructure,reinforced particle distribution,micro-hardness,corrosion behavior and in-vitro bioactivity were *** subsequent FSP passes of WE43 alloy and WE43/n HA composite refined the grain size which was reduced by 94.29%and 95.92%(2.63 and 1.88μm,respectively)compared to base metal after three *** resulted in increasing the microhardness by 120%(90.86 HV0.1)and 135%(105.59 HV0.1)for the WE43 and WE43-n HA,*** is found that increasing FSP passes improved the uniform distribution of n HA particles within the composite matrix which led to improved corrosion resistance and less degradation *** corrosion rate of the FSPed WE43/n HA composite after three passes was reduced by 38.2%(4.13 mm/year)and the degradation rate was reduced by 69.7%(2.87 mm/y).This is attributed to secondary phase(Mg24Y5and Mg41Nd5)particle fragmentation and redistribution,as well as a homogeneous distribution of n ***,the growing Ca-P and Mg(OH)2layer formed on the surface represented a protective layer that reduced the degradation *** wettability test revealed a relatively hydrophilic surface with water contact angle of 49.1±2.2°compared to 71.2±2.1°for base ***,biomineralization test showed that apatite layer grew after immersion 7d in simulated body fluid with atomic ratio of Ca/P 1.60 approaching the stoichiometric ratio(1.67)indicating superior bioactivity of FSPed WE43/n HA composite after three *** results raise that the grain refinement by FSP and introduction of n HA partic

关键词： Friction stir processing Magnesium-based composite Nano-hydroxyapatite Corrosion behavior In-vitro bioactivity

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A superior strength-ductility synergy of Al_(0.1)CrFeCoNi high-entropy alloy with fully recrystallized ultrafine grains and annealing twins

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Journal of Materials Science & Technology 2022年第36期131卷 185-194页

作者： Jiahao li Kejie Lu Xiaojun Zhao Xinkai Ma fuguo li Hongbo Pan Jieming Chen Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengdu 610031China Shenzhen Institute of Southwest Jiaotong University Shenzhen 518000China State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Anhui Province Key Laboratory of Metallurgical Engineering&Resources Recycling(Anhui University of Technology) 243002 MaanshanChina Luoyang Ship Material Research Institute Luoyang 471023China

Grain refinement usually makes the materials stronger,while ductility has a dramatic ***,a superior tensile strength–ductility synergy in a fully recrystallized ultrafine-grained(UFG)Al_(0.1)CrFeCoNi with abundant annealing twins was achieved by cold rolling at room temperature and short-time *** microstructure characterization using electron backscattered scattering diffraction demonstrates that abundant geometrically necessary dislocations(GNDs)gather around the grain boundaries and twin boundaries after tensile *** coarse-grained(CG)samples undergo a larger plastic deformation than UFG samples,the GND density decreases with grain size ranging from UFG to *** electron microscopy results reveal that the annealing twin boundary,which effectively hinders the dislocation slip and stores dislocation in grain interior,and the activation of multiple deformation twins are responsible for the superior strength–ductility synergy and work hardening *** addition,the yield strength of fully recrystallized Al_(0.1)CrFeCoNi follows a Hall–Petch relationship(σ_y=24+676d^(–1/2)),where d takes into account both grain boundaries and annealing twin *** strengthening effects of grain boundaries and annealing twin boundaries were also evaluated separately.

关键词： High-entropy alloy Ultrafine grains Annealing twins Strength Ductility

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Microstructure-based Simulation of Plastic Deformation Behavior of SiC Particle Reinforced Al Matrix Composites

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Chinese Journal of Aeronautics 2009年第6期22卷 663-669页

作者： Zhang Peng li fuguo School of Materials Science and Engineering Northwestern Polytechnical University Xi 'an 710072 China

This article, in order to unearth the deformation mechanism of particle reinforced metal matrix composites, establishes a finite element model （FEM） based on the actual microstructures. It finds out and analyzes the distribution of von Mises effective stress, strain and the maximum principal stress in the matrix and particles. Moreover, the overall stress and strain in the matrix and composites are calculated. By comparison, a tiny discrepancy exists between the experimental results and the simulation with respect to flow stresses. The effects of deformation parameters, such as temperature and strain rate, on the strengthening mechanism are explored and proved to be weak.

关键词： metal matrix composites deformation simulation cell model microstructure

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Statistical Analysis of Reinforcement Characterization in SiC Particle Reinforced Al Matrix Composites

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Journal of Materials Science & Technology 2009年第6期25卷 807-813页

作者： Peng Zhang fuguo li School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 China

The characterization of reinforcement in 15% SiC particles reinforced AI matrix composites processed by powder metallurgy route was studied by statistical method. During the analysis, a new approach for the estimation of the characterization of reinforcement was presented. The mathematic software MATLAB was used to calculate the area and perimeter of reinforcement, in which the image processing technique was applied. Based on the calculation, the fractal dimension, shape factor, reinforcement size distribution and reinforcement distribution were investigated. The results show that the reinforcement shape is similar to rectangle; the reinforcement size distribution is broad with the＇ range of 1-12 μm; the topography of reinforcement is smooth; and the reinforcement distribution is inhomogeneous. Furthermore, the cell model based on the statistical characterization was established and tested.

关键词： Particle reinforced AI matrix composites Fractal dimension Shape factor Distribution Cell model

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Phase-field Simulation of Microstructural Evolution during Preparation of Semi-solid Metal by Electromagnetic Stirring Method

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Journal of Materials Science & Technology 2006年第4期22卷 441-446页

作者： Xiaolu YU fuguo li Yuanchun REN Miaoquan li School of Materials Science and Engineering Northwestern Polytechnical University Xi＇an 710072 China

In the process of preparation of semi-solid metal materials, a variety of factors would influence the preparing time and the morphology of non-dendritic microstructure. The aim of this work is using phase-field method to simulate non-dendritic growth during preparation of AI-4Cu-Mg semi-solid alloy by electromagnetic stirring method （EMS method）. Several factors such as the disturbance intensity, anisotropy, the thickness of the interface and the ratio of diffusivity in solid and liquid were considered. It is shown that decreasing the thickness of the interface results in more circular outline of particles, and increasing the diffusivity in solid can reduce degree of microsegregation. The disturbance intensity in the model can be connected with current intensity of stator or magnetic induction density impressed. Simulation results show that the larger the disturbance intensity or magnetic induction density, the more globular morphology the original phase in the matrix.

关键词： Semi-solld metal Phase-field method Microstructure Simulation

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Influences of pre-torsion deformation on microstructure and mechanical properties of pure titanium subjected to subsequent tension deformation

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Chinese Journal of Aeronautics 2018年第4期31卷 837-844页

作者： Jie liU fuguo li Han CHEN School of Aeronautics Northwestern Polytechnical University Xi'an 710072 China State Key Laboratory of Solid cation Processing School of Materials Science and Engineering Northwestern Polytechnical University Xi'an 710072 China

A series of experimental studies was carried out to investigate the influences of pretorsion on microstructure evolution, mechanical properties, and fracture appearance of pure titanium subjected to subsequent tension deformation. An introduction of pre-torsion strain can improve the materials＇ mechanical properties through micro hardness evaluation. That is, the micro hardness of tensile samples with pre-torsion deformation is much higher than that of samples processed by single torsion or tension. It can be seen from the microstructure that pre-torsion deformation can be used to refine grains better and control grains＇ morphology by combining subsequent tension. The results indicate that the grains are refined most evidently for tensile samples with 2 turn pre-torsion deformation. Moreover, fracture analysis indicates that tensile samples with pre-torsion strain can present good comprehensive performance. In conclusion, pre-torsion deformation plays an important role in improving comprehensive performance and controlling microstructure evolution on pure titanium subjected to later tension deformation.

关键词： Combined torsion and tension Fracture Mechanical properties Microstructure Pre-torsion Titanium

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Forming limit Stress Diagram Prediction of Aluminum Alloy 5052 Based on GTN Model Parameters Determined by In Situ Tensile Test

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Chinese Journal of Aeronautics 2011年第3期24卷 378-386页

作者： HE Min li fuguo WANG Zhigang School of Materials Science and Engineering Northwestern Polytechnical University Xi 'an 710072 China Department of Mechanical Science and Engineering Xuzhou Institute of Technology Xuzhou 221008 China Department of Aircraft Structure Design and Research the First Aircraft Institute Aviation Industry Corporation of China Xi 'an 710089 China

The conventional forming limit diagram （FLD） is described as a plot of major strain versus minor strain. However, FLD is dependent on forming history and strain path. In the present study, a forming limit stress-based diagram （FLSD） has been adopted to predict the fracture limit of aluminum alloy （AA） 5052-O1 sheet. Nakazima test is simulated by plastic constitutive formula derived from the modified Gurson-Tvergaard-Needleman （GTN） model. An in situ tensile test with scanning electron microscope （SEM） is proposed to determine the parameters in GTN model. The damage evolution is observed and recorded, and the parameters of GTN model are identified through counting void fraction at three damage stages of AA5052-O 1. According to the experimental results, the original void volume fraction, the volume fraction of potential nucleated voids, the critical void volume fraction, the void volume fraction at the final failure of material are assigned as 0.002 918, 0.024 9, 0.030 103, 0.048 54, respectively. The stress and strain are obtained at the last loading step before crack. FLSD and FLD of AA5052-O 1 are plotted. Compared with the experimental Nakazima test and uniaxial tensile test, the predicted results show a good agreement. The parameters determined by in situ tensile test can be applied to the research of the forming limit for ductile metals.

关键词： forming limit stress diagram GTN model in situ tensile test void damage aluminum alloy 5052-O1 sheet metal forming

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Description of shape characteristics through Fourier and wavelet analysis

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Chinese Journal of Aeronautics 2014年第1期27卷 160-168页

作者： Yuan Zhanwei li fuguo Zhang Peng Chen Bo State Key Laboratory of Solidification Processing Northwestern Polytechnical University

In this paper, Fourier and Wavelet transformation were adopted to analyze shape char- acteristics, with twelve simple shapes and two types of second phases from real microstructure mor- phology. According to the results of Fast Fourier transformation （FFT）, the Fourier descriptors can be used to characterize the shape from the aspects of the first eight Normalization amplitudes, the number of the largest amplitudes to inverse reconstruction, similarity of shapes and profile roughness. And the Diepenbroek Roughness was rewritten by Normalization amplitudes of FFT results. Moreover, Sum Square of Relative Errors （SSRE） of Wavelet transformation （WT） signal sequence, including approximation signals and detail signals, was introduced to evaluate the simi- larity and relative orientation among shapes. As a complement to FFT results, the WT results can retain more detailed information of shapes including their orientations. Besides, the geometric sig- natures of the second phases were extracted by image processing and then were analyzed by means of FFT and WT.

关键词： Fourier analysis Roughness measurement Shape characteristics Similarity Wavelet analysis

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Single-cell transcriptomic atlas of goat ovarian aging

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Journal of Animal Science and Biotechnology 2024年第1期15卷 146-161页

作者： Dejun Xu Shuaifei Song fuguo Wang Yawen li Ziyuan li Hui Yao Yongju Zhao Zhongquan Zhao Chongqing Key Laboratory of Herbivore Science College of Animal Science and TechnologySouthwest UniversityChongqing 400715China

Background The ovaries are one of the first organs that undergo degenerative changes earlier in the aging process,and ovarian aging is shown by a decrease in the number and quality of ***,little is known about the molecular mechanisms of female age-related fertility decline in different types of ovarian cells during aging,especially in ***,the aim of this study was to reveal the mechanisms driving ovarian aging in goats at single-cell *** For the first time,we surveyed the single-cell transcriptomic landscape of over 27,000 ovarian cells from newborn,young and aging goats,and identified nine ovarian cell types with distinct gene-expression *** enrichment analysis showed that ovarian cell types were involved in their own unique biological processes,such as Wnt beta-catenin signalling was enriched in germ cells,whereas ovarian steroidogenesis was enriched in granulosa cells(GCs).Further analysis showed that ovarian aging was linked to GCs-specific changes in the antioxidant system,oxidative phosphorylation,and ***,we identified a series of dynamic genes,such as AMH,CRABP2,THBS1 and TIMP1,which determined the fate of ***,FOXO1,SOX4,and HIF1A were identified as significant regulons that instructed the differentiation of GCs in a distinct manner during ovarian *** This study revealed a comprehensive aging-associated transcriptomic atlas characterizing the cell typespecific mechanisms during ovarian aging at the single-cell level and offers new diagnostic biomarkers and potential therapeutic targets for age-related goat ovarian diseases.

关键词： Goat Granulosa cells Ovarian aging Single-cell transcriptomic

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Optimization of structural parameters for elliptical cross-section spiral equal-channel extrusion dies based on grey theory

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Chinese Journal of Aeronautics 2013年第1期26卷 209-216页

作者： Wang Chengpeng li fuguo Lu Hongya Yuan Zhanwei Chen Bo State Key Laboratory of Solidification Processing Northwestern Polytechnical University Department of Mechanical Engineering Tsinghua University

The elliptical cross-section spiral equal-channel extrusion （ECSEE） process is simulated by using Deform-3D finite element software. The ratio m of major-axis to minor-axis length for ellipse-cross-section, the torsion angle u, the round-ellipse cross-section transitional channel L1, the elliptical rotation cross-section transitional channel L2 and the ellipse-round cross-section transitional channel L3 are destined for the extrusion process parameters. The average effective strain eave on cross-section of blank, the deformation uniformity coefficient a and the value of maximum damage dmax are chosen to be the optimize indexes, and the virtual orthogonal experiment of L16 （45） is designed. The correlation degree of the process factors affecting eave, a and dmax is analyzed by the numerical simulation results using the weights and grey association model. The process parameters are optimized by introducing the grey situation decision theory and the ECSEE optimal combination of process parameters is obtained： u of 120 , m of 1.55, L1 of 7 mm, L2 of 10 mm, and L3 of 10 mm. Simulation and experimental results show that the material can be refined with the optimized structural parameters of die. Therefore, the optimization results are satisfactory.

关键词： Correlation degree Elliptical cross-section spiral equal-channel extrusion (ECSEE) Grey theory Optimization Orthogonal design Simulation

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