材料期刊网

INFLUENCE OF GRAIN BOUNDARY MORPHOLOGY ON CREEP AND FRACTURE BEHAVIOURS OF SUPERALLOYS IN SULFUR-CONTAINING ENVIRONMENT

ZHANG Yuanhu SUN Jian XIANG Yi HU Gengxiang Shanghai Jiaotong University , Shanghai , ChinaLI Tiefan Institute of Corrosion and Protection of Metals , Academia Sinica , Shenyang , China Yuanhu , Department of Materials Science and Engineering , Shanghai Jiaotong University , Shanghai , 200030

金属学报(英文版)

Studies on the high temperature creep and fracture behaviours in air or in SO_2 contaminated environment for the Fe-base superalloy GH302 with flat or zigzag grain boundaries(GB) and the Ni-base superalloy Rene 80 were carried out.Although the creep rupture properties of the GH302 with zigzag GB was remarkably superior to that of flat GB in air,the properties of both droped dramatically in 10% SO_2-air environment,the creep rupture properties of the directional solidified Rene 80 were much better than that of the conventionally cast alloy in air,and also kept the same property in SO_2 contaminated environment as in air.Owing to the interaction between creep and sulphidation,the failure mechanism relates to the formation of molten Ni-Ni-3S_2 eutectic along GB,led to the premature failure of the alloy.

关键词: superalloy , null , null , null , null

Rheological Behaviour of Steel ZG15CrMoV and Carbon Steel 35 at High Temperatures

XU Dong AN Geying LI Qingchun Institute of Materials Science and Engineering , Shanghai Jiao Tong University , Shanghai , 200030 , ChinaDept.of Metallic Materials and Technology , Harbin Institute of Technology , Harbin , 150006 , ChinaTo whom correspondence should be ad

材料科学技术（英文）

关键词: steel , null , null

Atomistic Simulation of Interaction between Grain Boundary and Dislocations in Ni_3Al

Dongliang LIN(T.L.Lin) Da CHEN Min LU Department of Materials Science , Shanghai Jiaotong University , Shanghai , 200030 , China

材料科学技术（英文）

The embedded atom type potentials and static relaxation method combined with a steepest decent computational technique have been used to simulate the interaction between the grain boundary (GB) and dislocations in Ni_3Al alloys.The focus has been placed on the energy feature of the interaction,the distortion of GB structural units,and the dislocation core structure near the GB.Im- plication has also been made on the results for the understanding of the mechanism responsible for B-enhanced ductility.

关键词: atomistic simulation , null , null , null

Cyclotron Resonance of Free Magnetopolaron in Quantum Well Wires

Haiyang ZHOU Kadi ZHU Shiwei GU Dept.of Applied Physics , Jiaotong University , Shanghai , 200030 , China

材料科学技术（英文）

The cyclotron resonance of magnetopolaron in quantum well wires (QWWs) have been studied with the use of variational solutions to the effective mass equation. The results show that both the abso- lute value of the electron-phonon interaction energy and the cyclotron resonance frequency de- crease with the increase of the sizes of QWWs, and also that the cyclotron resonance frequency in- creases with the external magnetic field.

关键词: cyclotron resonance , null , null

STUDY ON THE THREESTAGE CREEP OF THE DD3SINGLE CRYSTAL SUPERALLOY

Author X.A. Zhang1) , H.Q. Xia1) , Z.T. Wu1) , Y.F. Han1) , R. Shi2) and G.X. Hu2) \= 1) Mechanical Properties Laboratory , Beijing Institute of Aeronautical Materials , Beijing 100095 , China2) The State Education Commission Open Research Laboratory for High Temperature

金属学报(英文版)

Materials and Testing, Shanghai Jiao Tong University, Shanghai 200030, ChinaManuscript received 18 October 1998 The threestage creep behavior of DD3 single crystal superalloy had been studied. The results show that the creeprupture properties of DD3 single crystal satisfy the requirements for high performance turbine blade application. The influence of crystal orientation on the creeprupture property of DD3 single crystal was tested and discussed. An engineering criterion to evaluate the regimes of secondary and tertiary creep is proposed, and this method gives a reasonable result for practical applications. The fractography and TEM micrography of the tested specimens had been studied, and it is determined that the glidecontrolled creep is the basic creep mechanism of DD3 single crystal at intermediate temperature, but the thermally activated processes become dominant at higher temperature.

关键词: threestage creep curve , null , null , null