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electronic and magnetic structures of V-doped zinc blende Zn_(1-x)V_xN_yO_(1-y) and Zn_(1-x)V_xP_yO_(1-y)

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Chinese Physics B 2011年第8期20卷 419-424页

作者： N.mamouni m.Belaiche A.Benyoussef A.el Kenz h.ez-Zahraouy m.Loulidi e.h.Saidi e.K.hlil Laboratoire de magntisme et de Physique des hautes energies Dpartement de Physique Associ au CNRSTURACB.P.1014Facult des SciencesRabatMorocco Laboratoire de magntisme Matriaux MagntiquesMicro-ondes et CramiqueENSRabatMorocco INANOTeCh Institute of Nanomaterials and NanotechnologyMAScIRRabatMorocco Laboratoire de Physique des hautes energies Dpartement de Physique B.P.1014Facult des SciencesRabatMorocco Institut Nel MCMF-UJFC.N.R.SB.P.16638042 Grenoble CedexFrance

electronic and magnetic structures of zinc blende ZnO doped with V impurities are studied by first-principles calculations based on the Korringa-Kohn-Rostoker （KKR） method combined with the coherent potential approximation （CPA）. Calculations for the substitution of O by N or P are performed and the magnetic moment is found to be sensitive to the N or P content. Furthermore, the system exhibits a half-metallic band structure accompanied by the broadening of vanadium bands. The mechanism responsible for ferromagnetism is also discussed and the stability of the ferromagnetic state compared with that of the paramagnetic state is systematically investigated by calculating the total energy difference between them by using supercell method.

关键词： ab initio calculations density of states magnetic moment doping diluted magneticsemiconductors

Characterization of surface liquid segregation in SSm-hPDC aluminium alloys 7075,2024,6082 and A201

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中国有色金属学会会刊：英文版 2010年第S3期20卷 847-851页

作者： h.mLLeR U.A.CURLe e.P.mASUKU materials Science and manufacturing Council for Scientific and Industrial Research(CSIR)PretoriaSouth Africa

The surface liquid segregation(SLS) phenomenon in semi-solid metal-high pressure die casting(SSm-hPDC) plates of 7075,2024,6082 and A201 was investigated by different *** profiles were determined by firstly measuring the chemical composition of the surface of the plates using a Thermo Quantris optical emission spectrometer(OeS).material was then removed by a grinding process followed by measurement of the amount of material removed and chemical *** profiles of the main alloying elements were plotted for the cross-section of the plates in the as-cast and T6(after solution treatment) temper *** hardness profiles from the surface to the centre of the plates were *** samples of cross-sections of the castings were prepared and evaluated using a scanning electron *** results show that surface liquid segregation in SSm-hPDC alloys causes significant differences in properties between the surface and the bulk of these castings in both the F and T6 temper conditions.

关键词： semi-solid metal(SSm) forming alloy 7075 alloy 2024 alloy 6082 alloy A201 surface liquid segregation

effect of Phase Transformation During Long-Term Solution Treatment on microstructure,mechanical Properties,and Bio-corrosion Behavior of mg–5Zn–1.5Y Cast Alloy

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Acta metallurgica Sinica(english Letters) 2018年第6期31卷 561-574页

作者： h.Jafari e.heidari A.Barabi m.Dashti Kheirabadi materials engineering Department Faculty of Materials Engineering and Modern TechnologiesShahid Rajaee Teacher Training University

The influence of long-term solution treatment for various intervals on the microstructure,mechanical properties,and corrosion resistance of the as-cast mg–5Zn–1.5Y alloy was *** of secondary phases was studied during solution treatment through thermal analysis test and thermodynamic *** and hardness tests,as well as polarization and immersion tests,were performed to evaluate the mechanical properties and corrosion behavior of the ascast and heat-treated alloy,*** show that solution treatment transforms I-phaseinto W-phaseas well as dissolves it into the a-mg matrix to some extent;therefore,the amount of W-phase ***,prolonged solution treatment decreases the volume fraction of the *** the first stage of solution treatment for 14 h,the tensile properties significantly increase due to the incomplete phase *** long-term solution treatment sharply decreases the tensile and hardness properties of the alloy,it improves the corrosion resistance due to the transformation of I-phase into *** fact,it decreases corrosion potential and simultaneously dissolves intermetallic compounds into the a-mg matrix,resulting in the reduction in galvanic microcells between the matrix and *** is found that the optimum time for long-term solution treatment is 14 h,which improves both corrosion behavior and mechanical properties.

关键词： magnesium alloy Long-term solution treatment microstructure mechanical properties Bio-corrosion

Cu-（B4C）p metal matrix composites processed by accumulative rollbonding

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Progress in Natural Science:materials International 2016年第6期26卷 613-620页

作者： S.mansourzadeh m.hosseini e.Salahinejad A.h.Yaghtin Department of materials Science and engineering College of Chemical and Metallurgical EngineeringShiraz BranchIslamic Azad University Department of materials Science and engineering School of EngineeringShiraz University Faculty of materials Science and engineering K.N.Toosi University of Technology

In this study, Cu/B4C metal matrix composites were prepared by accumulative roll-bonding（ARB）. The microstructure of the processed samples was characterized by Tem, Sem and optical microscopy. The microhardness, uniaxial tensile and four-point probe tests were carried out to evaluate the mechanical properties and electrical resistivity of the ARBed monolithic and composite samples. The results showed that the reinforcement distribution was improved by increasing ARB cycles, which was quantitatively confirmed by some models. Based on Tem observations, the formation of an ultrafine grained structure in the composite matrix was also approved. It was shown that with increasing ARB cycles, the microhardness and tensile strength of the monolithic Cu samples were enhanced up to the 3rd cycle and then saturated, but the microhardness and tensile strength of the composites showed an increasing trend to the last cycle. Apart from a substantial improvement in the mechanical properties of the Cu/B4C composites, a minor decrement in electrical conductivity was detected after six ARB cycles.

关键词： electron microscopy mechanical characterization Composites

Application of shortened heat treatment cycles on A356 automotive brake calipers with respective globular and dendritic microstructures

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Transactions of Nonferrous metals Society of China 2010年第9期20卷 1780-1785页

作者： h.mLLeR G.GOVeN DeR W.e.STUmPF materials Science and manufacturing Council for Scientific and Industrial Research (CSIR) Department of materials Science and metallurgic al engineering University of Pretoria

Since the automotive industry has many possible applications for semi-solid metal (SSm)-high-pressure die casting (hPDC) parts, the newly developed heat treatment cycles, as well as the traditional heat treatment cycles, were applied to A356 brake calipers cast using a LK DCC630 hPDC *** hardness measurements at a cross section of the brake calipers were performed, indicating that similar values can be obtained when using the significantly shorter heat treatment ***, the typical tensile properties that can be obtained for SSm-hPDC A356 brake calipers are compared with those manufactured by gravity die *** indicate that the differences in microstructures (globular or dendritic) do not have a noteworthy effect on the heat treatment *** implies that the short heat treatment cycles originally developed for globular SSm-hPDC A356 castings can be successfully applied to dendritic liquid A356 castings too.

关键词： semi-solid metal (SSm) forming heat treatment A356 brake caliper gravity die casting automotive

Corrosion resistance of powder injection moulded titanium in physiologic serum and artificial saliva

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Acta metallurgica Sinica(english Letters) 2010年第3期23卷 197-205页

作者： S.Candan m.Turkmen h.Ahlatci e.Candan Department of metals Karabuk University

most of dental implants are made from titanium or titanium based ***, one of the drawback of such implants is high cost due to the technological difficulties in casting method or *** this work, powder injection moulding（PIm） method has been used in order to explore lower cost implants without minimising the biocorrosion resistance of the *** resistance of titanium specimens, produced by powder injection moulding method（PIm-Ti）, in physiologic serum and artificial saliva was *** pure bulk Ti（CP-Ti） was used as control *** oxidation was also carried out to both PImTi and CP-Ti *** and corrosion resistance were investigated using microhardness, X-ray diffraction（XRD）, scanning electron microscopy（Sem） and potentiodynamic polarization *** microstructure of PIm-Ti samples contained porosity as compared to CP-Ti control *** of PIm-Ti samples varied with varying applied load whereas it was free from applied load for CP-Ti control *** measurements and Sem analysis revealed that corrosion behaviour of PIm-Ti was reasonably as good as CP-Ti both in as-produced and oxidized conditions in physiologic serum and artificial saliva in spite of its porous structure.

关键词： Titanium Powder injection moulding Corrosion Oxidation

Light management with quantum nanostructured dots-in-host semiconductors

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Light(Science & Applications) 2021年第12期10卷 2399-2407页

作者： m.Alexandre h.Águas e.Fortunato R.martins m.J.mendes i3N/CeNImAT Department of Materials ScienceFaculty of Science and TechnologyUniversidade NOVA de Lisboa and CEMOP/UNINOVACampus de Caparica2829-516 CaparicaPortugal

Insightful knowledge on quantum nanostructured materials is paramount to engineer and exploit their vast gamut of ***,a formalism based on the single-band effective mass equation was developed to determine the light absorption of colloidal quantum dots(CQDs)embedded in a wider bandgap semiconductor host,employing only three parameters(dots/host potential barrier,effective mass,and QD size).It was ascertained how to tune such parameters to design the energy level structure and consequent optical *** findings show that the CQD size has the biggest effect on the number and energy of the confined levels,while the potential barrier causes a linear shift of their *** smaller QDs allow wider energetic separation between levels(as desired for most quantumbased technologies),the larger dots with higher number of levels are those that exhibit the strongest ***,it was unprecedently shown that such quantum-enabled absorption coefficients can reach the levels(10^(4)–10^(5) cm^(−1))of bulk semiconductors.

关键词： quantum dots absorption

Co-,Fe-,Ni-doped and co-doped rutile GeO_(2):insights from ab-initio calculations

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Communications in Theoretical Physics 2022年第4期74卷 113-126页

作者： R essajai e Salmani m Bghour A Labrag F Goumrhar m Fahoume h ez-Zahraouy materials and Subatomic Physics Laboratory Faculty of SciencesIbn Tofail UniversityKenitraMorocco Group of Semiconductors and environmental Sensor Technologies-energy Research Center Faculty of ScienceMohammed V UniversityB.P.1014RabatMorocco Laboratory of Condensed matter and Interdisciplinary Sciences Department of PhysicsFaculty of SciencesMohammed V UniversityP.O.Box 1014RabatMorocco equipe des matériaux Supraconducteursàhaute température critique Department of PhysicsIbn Zohr UniversityFaculty of SciencesBP:8106AgadirMorocco Faculty of Applied Sciences Route Nationale N°10 citéAzrouAit MelloulIbn Zohr UniversityAit MelloulIbn Zohr UniversityMorocco higher School of education and Training of el Jadida(eSeF) Chouaib Doukkali UniversityEl Jadida 24000Morocco Laboratory of Physics of high energy Modeling&Simulations(LPHE-MS)Faculty of SciencesMohammed V University of RabatIbn BatoutaB.P.1014 RabatMorocco Laboratoire des Sciences de l’Ingénieur pour l’energie Ecole Nationale des Sciences Appliquées d’El Jadida(ENSA-J)BP 1166EL Jadida Plateau24002Morocco

Rutile germanium oxide(rutile GeO_(2)),a semiconductor,can act as a half-metallic compound and is a promising material for spintronic and optoelectronic *** were performed using the Korringa–Kohn–Rostoker(KKR)approach and the coherent potential approximation(CPA),which were further combined with two approximations,the local density approximation(LDA)and the self-interaction corrected LDA approximation(LDA-SIC),to study the electronic structure of bulk rutile GeO_(2) doped and co-doped with three transition-metal impurities:Fe,Co,and *** doping value was set to 10%,while the co-doping level was set to 5%for each *** main findings of this work are:(1)a direct ultrawide bandgap of4.80 eV is observed and the rutile GeO_(2) exhibits an N-type semiconducting property.(2)Doped and co-doped GeO_(2) acquire a magnetic behavior and exhibit half-metallicity.(3)The mechanism responsible for these properties is also studied.(4)The critical temperature can reach 334 K when GeO_(2) is doped with Fe,while it rises to 398 K when it is co-doped with Fe and Co.(5)The spin polarization can be improved by *** can be inferred that rutile GeO_(2) doped or codoped with(Co,Fe)transition metals can be considered to be potential candidates for spintronic and optoelectronic applications.

关键词： LDA approximation spintronic Curie temperature spin polarization LDA-SIC approximation rutile germanium oxide

Thermal Characteristics,mechanical Properties,In Vitro Degradation and Cytotoxicity of Novel Biodegradable Zn-Al-mg and Zn-Al-mg-xBi Alloys

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Acta metallurgica Sinica(english Letters) 2017年第3期30卷 201-211页

作者： h.R.Bakhsheshi-Rad e.hamzah h.T.Low m.h.Cho m.Kasiri-Asgarani S.Farahany A.mostafas m.medraj Advanced materials Research Center Department of Materials Engineering Najafabad Branch Islamic Azad University Najafabad Iran Department of materials Manufacturing and Industrial Engineering Faculty of Mechanical Engineering Universiti Teknologi Malaysia 81310 Johor Bahru Johor Malaysia Research and Development Centre KISWIRE Sdn. BhdJohor Bahru Johor Malaysia Department of materials and mechanical engineering Buein Zahra Technical University Qazvin *** Iran Department of mechanical and materials engineering Masdar Institute of Science and TechnologyP. O. Box: 54224 Masdar City Abu Dhabi UAE Department of mechanical engineering Concordia University 1455 De Maisonneuve Blvd. West Montreal QCH3G 1MS Canada

Ternary Zn-0.5A1-0.5mg and quatemary Zn-0.5A1-0.5mg-xBi （x = 0.1, 0.3 and 0.5） alloys were studied to evaluate the thermal and structural characteristics, mechanical properties, cytotoxicity and in vitro degradation behavior. Thermal analysis and microstructural observations showed that Zn-0.5A1-0.5mg is composed of FCC-A1 ＋ hCP- Zn ＋ mg2（Zn,A1）ll while a new phase a-mg3Bi2 appeared after the addition of Bi to the Zn-0.5A1-0.5mg ternary alloy. The results revealed that the quaternary Zn-A1-mg-Bi alloys have higher tensile strength, elongation and hardness but slightly lower corrosion resistance than those of the temary Zn-AI-mg alloy. Based on the mTT assay, the Zn-A1-mg and Zn-A1-mg-Bi alloys were found to be biocompatible, and thus, they can be considered for further investigation in an in vivo environment.

关键词： Zn-AI-mg-Bi microstructure mechanical property Corrosion Cytotoxicity