材料期刊网

EFFECTS OF Nb/Ti+ Nb MICRO ALLOYING ON 900℃ TENSILE PROPERTIES OF ALLOYGH652

Z.F.Peng1) , Y.Y.Ren1) , Q.S. Mei1) , Y.Q.Wang2) , X.Y.Zhang2) and M.S.Ye2) 1) Department of Materials Engineering , Wuhan University of Hydraulic and Electric Engineering , Wuhan430072 , China 2) Department of Superalloys , CentralIron and Steel Research Institute , Beijing430072 , 100081 China

金属学报(英文版)

Theeffectsof Nband Ti+ Nb microalloyingon mechanicalpropertiesand rupturelifeunder900 ℃ tensiletest on alloy GH652 were studied. Among theoriginalalloy GH652 and its Nb/ Ti+ Nb microalloyed alloys, the Ti+ Nb microalloyed alloy exhibited optimum com bined900℃ tensilestrength and plasticity and longer 900℃ 49 MPa prolonged tensile rup turelife as well. The role of refractory alloying elementscould be effectively brought intoplay with highertemperaturesolution treatment. Coordination strengthening of Matrix andgrain boundary wasthekeyfactoroflifetimeextension andthe mobilityof dislocationsinthematrix wasresponsableforthe plasticity ofthe micro alloyedsamples.

关键词: GH652 Nb/ Ti+ Nb micro alloying , null , null , null

Development of Cast Superalloys for Gas Turbines in China

CHEN Rongzhang CHEN Wanhua Institute of Aeronautic Materials , Beijing 100095 , China.

材料科学技术（英文）

As in other countries,significant achievements in the research of cast superalloys for many years have also been obtained in China.These results are important contribu- tion to the development of aero and land-based gas tur- bine engines.

关键词: cast superalloy , null

SPRAY FORMED NICKEL-BASE SUPERALLOYS

Z. Li , S.F. Tian , X.G. Zhao , Z.K. Liang , L.P. Ren , G.F.Mi and M.G. Yan(Bejing Institute of Aeronautical Materials , Beijing 100095 , China Manuscript received 26 August 1996)

金属学报(英文版)

In this paper,part of the research and development work in the field of spray formed superalloys at BIAM of China is briefly summarized. With an experimental spray forming facility,whose melting capacity is suitable for making disk and columnar shaped integral-dense and clean Ni-base superalloy preforms with low oxygen content,fine grain, uniform chemistry and improved forgeability, a series of Ni-base superalloys have been spray atomized and deposited, among which three alloys have been chosen for microstructural and mechanical properties evaluation.

关键词: :spray forming , null , null

Nitrogen in revert superalloys

Materials at High Temperatures

Two different ways of combining nitrogen in virgin and revert superalloy have been identified. The source of nitrogen in revert superalloy has been ascertained. It is found that nitrogen in scraps of virgin superalloy undergoes a transition from CrN to TiN when these scraps are remelted in VIM furnace. High nitrogen content in revert superalloys causes microporosity formation, that greatly deteriorates tensile and stress rupture properties of superalloys.

关键词: nitrogen;revert superalloy;microporosity

Change in Carbon Dioxide (CO2) Emissions From Energy Use in China′s Iron and Steel Industry

SUN Wenqiang , CAI Jiuju , MAO Hujun , GUAN Duojiao

钢铁研究学报(英文版)

As the largest energy consuming manufacturing sector and one of the most important sources of carbon dioxide (CO2) emissions, the China′s iron and steel industry has paid attention to the study of changing trend and influencing factors of CO2 emissions from energy use. The logarithmic mean Divisia index (LMDI) technique is used to decompose total change in CO2 emissions into four factors: emission factor effect, energy structure effect, energy consumption effect, and steel production effect. The results show that the steel production effect is the major factor which is responsible for the rise in CO2 emissions; whereas the energy consumption effect contributes most to the reduction in CO2 emissions. And the emission factor effect makes a weak negative contribution to the increase of CO2 emissions. To find out the detailed relationship between change in energy consumption or steel production and change in CO2 emissions, the correlation equations are also proposed.

关键词: CO2 emissions , energy use , LMDI technique , steel production , energy consumption

(alpha-PbO2-type nanophase of TiO2 from coesite-bearing eclogite in the Dabie Mountains, China

American Mineralogist

A natural high-pressure phase of titanium oxide with alpha-PbO2-structure has been found in omphacite from coesite-bearing eclogite at Shima in the Dabie Mountains, China. High-resolution transmission electron microscope observations have revealed an orthorhombic lattice, corresponding to alpha-PbO2-type TiO2, with cell parameters a = 0.461 nm, b = 0.540 nm, c = 0.497 nm and space group Pbcn. It occurs as nanometer-thick (< 2 nm) lamellae between multiple twinned rutile crystals, providing additional evidence of very high-pressure, metamorphism at 7 GPa, 900 degrees C. This implies subduction of continental material to a depth of more than 200 kilometers. alpha-PbO-type TiO2 could be an extremely useful index mineral for ultrahigh-pressure.

关键词: high-pressure phase;ries crater;rutile;polymorph;titanium

INTERMETALLICS AS SUBSTITUTES FOR SUPERALLOYS

J. Zhang , D. Feng , Z.Y. Zhong

金属学报(英文版)

The application advances of TiAl, Ti3Al and Ni3Al base alloys were demonstrated by Central Iron and Steel Research Institute, China. The recent research progresses on improving the reliability of cast TiAl were mainly presented and discussed. The characteristics of the self-oriented lamellar microstructure in cast TiAl were investigated in both as cast and as HIPed states. Based on the mechanical anisotropy of the cast lamellar microstructure, the component specific microstructure design was proposed for a better performance and reliability of cast TiAl.

关键词: intermetallic , null , null

RESEARCH ON REFRACTORY SUPERALLOYS IN THE HTM 21 PROJECT

Y.F.Gu , Y.Yamabe-Mitarai , C.Huang , H.Harada

金属学报(英文版)

It was proposed that a new class of alloys based on platinum group metals (PGMs) were calle drefractory superalloys. These refractory superalloys have an fcc and L12 coherent two-phase structure (similar to that of Ni-based superalloys), high melting temperatures and good potential as structural materials used at temperatures up to 1800℃. Our recent results on the microstructure evolution, deformation and fracture behavior of some of these refracotry superaUoys, especial lr- and Rh-base refractory superalloys were reported.

关键词: platinum group metals , null , null

STATISTICAL EVALUATION OF CRITICAL INCLUSION FACTOR FOR SECONDARY RECRYSTALLIZATON IN 3%Si STEEL Lecturer,Department of Materials Engineering,Southwestern Jiaotong University,Chengdu 610031,China

LI Shuchen Southwestern Jiaotong University , Chengdu , ChinaCHEN Mengzhe KE Jun University of Science and Technology Beijing , Beijing , China

金属学报(英文版)

On the basis of statistical data of MnS in the conventional 3% Si steel sheeets after various annealing processes,the critical inclusion factor has been evaluated to be 20 mm~(-1).The inhi- bition of MnS to grain growth has been exactly described.

关键词: 3%Si steel , null , null

CORRELATION BETWEEN STRESS COMPONENTS AND STRESS CORROSION CRACKS IN BRASS Lecturer,Department of Materials Physics,University of Science and Technology Beijing,Beijing 100083,China

QIAO Lijie LIU Rui XIAO Jimei University of Science and Technology Beijing , Beijing , China

金属学报(英文版)

The effects of stress components on nucleation sites and propagation directions of stress cor- rosion cracks in brass were investigated with specimens under mode Ⅱ and mode Ⅲ loadings. The results indicated that under mode Ⅱ loading,stress corrosion cracks nucleated on the site with maximum normal stress component and propagated along the plane perpendieular to the maximum normal stress,under mode Ⅲ loading,the stress corrosion crack was not evident on the 45°plane due to the general corrosion in aqueous solution with high NH_4OH concentra- tion,while stress corroded in aqueous solution with low NH_4OH concentration, numerous cracks with spacings of 10—150μm were found on the 45°plane with maximum normal stress and no stress corrosion cracks was observed on the plane with maximum shear stress.

关键词: stress corrosion cracking , null , null , null