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Correlation of the Mechanical Properties of Polycrystalline Ni_3Al Alloys with Their Electronic Structure

Wen DENG Liangyue XIONG Chiwei LUNG International Centre for Materials Physics , Institute of Metal Research , Academia Sinica , Shenyang , 110015 , ChinaShuhe WANG Jianting GUO Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China

材料科学技术(英文)

The electronic structure of Ni_3Al alloys with different B contents has been investigated by measuring the positron lifetime spectra.The segregation of B atoms to defects could form strong covalent bondings with Ni and Al atoms and make the electronic structure in those locations similar to that in bulk,thus strengthen their cohesion.The interaction of B atoms,which were solid-solutioned in the crystal lattice of Ni_3Al in a manner of occupying interstitial sites,with Ni and Al atoms resulted in the increase of the density of valent electrons,thus increased the bonding cohesion in bulk.The im- provement of the mechanical properties of Ni_3Al alloys by B doping was due to both“grain bounda- ry effect”and“bulk effect”of B,which correlated with their electronic structure.

关键词: electronic structure , null , null , null

Local Enrichment of Active Element Y in Y-modified PVD Films on Mild Steel Substrate

LIU Changqing WU Weitao JIN Zhujing DAI Shaoxia WANG Wenhao Corrosion Science Laboratory , Institute of Corrosion and Protection of Metals , Academia Sinica , Shenyang , 110015 , ChinaInstitute of Metal Research , Academia Sinica , Shenyang , 110015 , ChinaTo whom correspo

材料科学技术(英文)

By means of EPMA,SIMS and XTEM tech- niques,the element distribution at the transition zone of Y-modified ion plated titanium and titanium nitride film on A3 steel substrate and the variation of the element content on the surface of the evaporation source before and after service were studied in detail.A mode was proposed in terms of preferential evaporation and micro-tunnel trans- portation of Y at the interface of film/substrate.

关键词: Y-enrichment , null , null , null

Vinylon Reinforced Aluminium Laminate

Guoxin SUI Zhongguang ZHENG Chengti ZHOU Changxu SHI Institute of Metal Research , Academia Sinica , Shenyang , 110015 , ChinaBenlian ZHOU International Centre for Materials Physics , Academia Sinica , Shenyang , 110015 , China

材料科学技术(英文)

A new kind of superhybrid composite material,vinylon reinforced aluminium laminate (VIRALL),has been developed by laminating the vinylon/epoxy prepreg layers and the aluminium alloy sheets alternatively.The mechanical properties of VIRALL laminate have been tested and the results are dis- cussed in terms of laws of mixtures.About a 24% increase in tensile strength and a 36%decrease in tensile modulus to that of the corresponding aluminium were found,which kept good agreement with the laws of mixtures.Compared with the corresponding aluminium,VIRALL has lighter density and lower price.VIRALL is hoped to be a partial substitute for the civil aluminium alloy in the future.

关键词: composite material , null , null , null , null , null

Oxygen Relief/Absorption and Superconductivity of Bi-Pb-Sr-Ca-Cu-O Compounds

QIN Zuoxiang , ZHANG Yansheng , ZHU Naiping Department of Materials Engineering , Dalian Railway Institute , Dalian , 116022 , China.Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China.

材料科学技术(英文)

The oxygen relief/absorption,superconduc— tivity and structure of(Bi_(1-x)Pb_x)_2Sr_2Ca_2— Cu_3O_y compounds have been studied by TGA, electrical resistance measurement and X-ray diffraction.The amount of oxygen which can be re- leased and superconductivity of the compounds are correlative to Pb content.The release of oxygen in- creases when x less than 0.2 and decreases when x exceeds 0.2 with increasing x.The appropriate con- tent of Pb for superconductivity is in the range of 0.1

关键词: oxygen relief/absorption , null , null , null

EFFECT OF AGING ON HYDROGEN EMBRITTLEMENT SUSCEPTIBILITY OF STEEL Cr21Ni6Mn9N

LIU Jianchao GUO Yunyi XING Zhongshu SHI Changxu Institute of Metal Research , Academia Sinica Shenyang , China LIANG Wubiao No.2 Automobile Factory , Shiyan , Hubei , China Professor , Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China

金属学报(英文版)

Effects of 650℃ aging for 1—1000 h on structure and hydrogen embrittlement susceptibility (HES)of steel Cr21Ni6Mn9N have been investigated.The results show that M_(23)C_6 type carbide precipitates at grain boundaries and Cr-depletive region appears beside them during aging.The precipitates grow and connect each other as the aging time prolongs.Meanwhile, the degree of Cr-depletion aggravates first and then recovers gradually while the aging time is very long,i.e.,1000 h.The HES of the steel increases with increasing aging time but does not reduce with the recovery of Cr content at the Cr-depletive region.That implies that the ex- isting of carbides at grain boundaries might be the main reason which promotes the HES of steel during aging.

关键词: aging , null , null , null

(α+β)Dual Phase CuZnAl Shape Memory Alloy

ZHAO Xu , QI Min , YANG Dazhi Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China.Department of Materials Engineering , Dalian University of Technology , Dalian , 116012 , China.

材料科学技术(英文)

The effect of α phase on CuZnAl shape memo- ry alloy(SMA)has been systematically studied by electrical resistance method,quantitative measure- ment of micrography and transmission electron microscopy(TEM).It is found that,by controlling the amount of α phase in(α+β)-CuZnAl alloy, phase transformation temperatures can be adjusted precisely in a wide range,while the good shape memory effect of CuZnAl is kept.In a word, quenching from(α+β)dual phase region is a rea- sonable method of adjusting phase transformation temperatures for CuZnAl alloy.

关键词: (α+β)-CuZnAl alloy , null , null

Sulphidation of Fe-Nb,Co-Nb and Ni-Nb Alloys in H_2-H_2S at 700℃

F.Gesmundo F.Viani Instituto di Chimica , Facolta di Ingegneria , Universita di Genova , Genova , 16129 , ItalyY.NIU Corrosion Science Lab. , Institute of Corrosion and Protection of Metals , Academia Sinica , Shenyang , 110015 , China

材料科学技术(英文)

The corrosion of alloys based on Fe,Co and Ni containing 15 and 30 wt-% Nb was studied at 700℃ in H_2-H_2S mixtures providing 10~(-8) atm S_2.The Fe and Co-based alloys formed duplex scales with an outer layer of pure base-metal sulphide and an inner layer containing both metals.The Nb addi- tions were not able to produce exclusive Nb sulphidation but yielded a significant decrease of the corrosion rates for both types of alloys with respect to the pure metals even though they were still much higher than that of pure Nb.The Ni-base alloys corroded rapidly forming a single complex scale layer,mainly due to the appearance of a liquid Ni-S solution.

关键词: niobium , null , null , null

Phase Transformations in ZrO_2 after Shock Loading

Sergey N.Kulkov Alexander G.Melnikov Institute of Strength Physics and Materials Science , The Russian Academy.of Science , Siberian Branch , Tomsk , 634055 , RussiaYanchun ZHOU Shengqi CHEN Zhe QU Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China

材料科学技术(英文)

The effects of shock loading on the morphology,grain growth during heating and phase transforma- tion of ZrO_2 have been investigated.It is shown that shock loading may be efficiently used to modify submicron ceramic powders with nanocrystalline structure.After shock loading,the critical diameter of ZrO_2 particles transformed from tetragonal to monoclinic decreased due to stored strain energy. Annealing of powders resulted in reversible transformation to the tetragonal without considerable grain growth up to 1200℃.

关键词: submicron ceramics , null , null , null

Studies of Correlations between Surface Composition Changes and Ion Bombardment Fluences of Multicomponent Materials

Liping ZHENG Xiqing XIA Mingyao LI Shanghai Institute of Nuclear Research , Academia Sinca , Shanghai , 201800 , ChinaRisheng LI Lab.of Atomic Imaging of Solids , Institute of Metal Research , Academia Sinica , Shenyang , 110015 , China

材料科学技术(英文)

Correlations between surface composition changes and ion bombardment fluences were studied for multicomponent materials by using a dynamic Monte Carlo program,including the preferential sputtering and bombardment-induced Gibbsian segregation (BIGS) processes.For the case of 1 keV KR-~(10)B_(0.02)~(11)B_(0.08) (the most simple multicomponent material system),it is found that the ~(10)B composition enriches at the surface at low fluences but depletes at the surface at high fluences.For the case of 1 keV Ar-Pt_(0.5)Cu_(0.5).it is found that the Cu composition at the topmost surface is always under the bulk composition between zero and high fluences,but the evident composition gradient of Cu(the segregation species) exists in the surface at low fluences.The effects of the preferential sputtering and BIGS processes on above two surface composition profiles are also discussed.

关键词: implantation , null , null

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