材料期刊网

First Cycle Effect of Polycrystalline CuZnAl Shape Memory Alloy during Thermal-Mechanical Cycling

Wenge LIU+ , Min ZHU , Dazhi YANG , Dept. of Materials Engineering , Dalian University of Technology , Dalian , 116024 , ChinaZhongguang WANG , State Key Laboratory for Fatigue and Fracture of Materials , Institute of Metal Research , Academia Sinica , Shenyang , 11001

材料科学技术（英）

The thermal-mechanical (T-M) cycles at constant strain of a polycrystalline CuZnAl alloy have been studied in the. present work. In-situ optical microscopic observations have been made to reveal the features of the phase transitions during T-M cycling. The variation of stress-temperature (S-T) curves and electrical resistance-temperature (R-T) curves accompanying with T-M cycling have been measured by tensile test and electrical resistance measurements. It has been found that the polycrystalline CuZnAl alloy shows apparent morphology changes and properties variations in the first cycle during T-M cycling which is called the first cycle effect in the present work. The stable transformation procedure in the T-M cycle is: martensiteparent phase +residual acicular martensite. This residual martensite possesses the character of stress-induced martensite.

关键词: CuZnAl shape memory alloy , null , null

ELEVATED AND ROOM TEMPERATURE MECHANICAL BEHAVIOR OF BORON DOPED NiAl ALLOYS

TAN YiDalian University of Technology , Dalian , ChinaSHINODA THitachi Research Laboratory , Hitachi Ltd. 391-12 Hitachi , JapanMISHIMA YTokyo Institute of Technology , Nagatuta. Midori-Ku , Yokohama 227 , JapanSUZUKI TDepartment of Metallurgical Engineering , Tokyo Institute of Technology. Ookayama , Meguro-Ku , Tokyo 152 , Japan

金属学报(英文版)

The effects of boron addition on defect hardening at room temperature and on high temperature creep properties are investigated in the B2 NiAl intermetallic compound. It is found that boron addition is effective on increasing the room temperature hardeness on the Ni-rich side but it has no effect on the A1-rich side of stoichiometry. These observations are attributed to interstitial dissolution of boron in Ni-rich NiAl and to a lack of solubility and also due to an enrichment at grain boundaries on the A1-rich side. The similar effect is found in high temperature creep resistance of NiAl by boron addition. The high temperature creep resistance increases on the Ni-rich side but it does not affect the A1-rich side of off-stoiciometry.

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INTERMETALLIC COMPOUNDS AND THEIR FORMATION REACTIONS IN SYSTEM Fe-Cr-Mo AT HIGH-TEMPERATURES

LIU Shicheng , Dalian Railway Insitute , Dalian , ChinaHamaguchi Yoshikazu , Kuwano Hisashi , Muroran Institute of Technology , Muroran , Japan

金属学报(英文版)

The stable ranges concerning the composition and temperature have been experimentally de- termined for the intermetallic compounds in system Fe-Cr-Mo at high-temperatures. The isothermal section of the Fe-Cr-Mo ternary phase diagram at 1250℃ and the formation re- actions for the intermetallic compounds, which are different in part from those shown in the literature, have been proposed.

关键词: Fe-Cr-Mo system , null , null , null , null

Positron Annihilation Study of the Quenched-in Vacancies in CuZnAl Alloys

Zhongguo WEI and Dazhi YANG (Dept. of Materials Engineering , Dalian University of Technology , Dalian , 116024 , China)

材料科学技术（英）

The excess vacancies in ternary CuZnAl and Ti-doped CuZnAl alloys quenched from temperatures between 673 K and 1223 K, and the behaviour of the quenched-in vacancies on postquench aging in martensite phase have been studied by Doppler broadening measurements. It has been found that adding Ti to the alloys resuIts in the formation of vacancy-Ti solute atom complexes which lowers the mobility of the vacancies. In the Ti-free alloy, the prominent changes in the lineshape S-parameter during the early stage of martensite aging have evidenced the occurrence of vacancy migration to sinks, clustering or vacancy related atomic distortion. The role of the vacancies in martensite stabilization has been discussed

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Catalysis on nano-carbon materials: Going where to? Preface

Catalysis Today

This contribution to the special issue of Catalysis Today is dedicated to selected contributions presented at the Carbocat-IV (Carbon for Catalysis) Symposium held in Dalian (China) on November 7-10 (2010). The introduction first shortly overviews the main reasons for the interest on carbon materials for catalysis and the elements of novelty discussed on the contributions of this issue, and then provide a concise outline of the general trends and developments in this field to give a glimpse on the progresses in the field, and on the perspectives of this exciting area of catalysis. (C) 2012 Elsevier B. V. All rights reserved.

关键词: Nano-carbon;Catalysis on carbon;Nanostructured carbon-based materials;Carbon hierarchy;ordered mesoporous carbon;metal-free;nanostructured carbon;activated;carbon;oxidative dehydrogenation;heterogeneous catalysis;sustainable;energy;counter electrode;porous carbons;fuel-cells