材料期刊网

RELATIONSHIP BETWEEN M-A CONSTITUENT AND CLEAVAGE FRACTURE BEHAVIOUR OF GRANULAR BAINITIC WELD METAL

XU Xiangxing SU Yi ZHOU Wei Tsinghua University , Beijing , ChinaCAI Qigong Central Iron and Steel Research Institute , Ministry of Metallurgical Industry , Beijing , China XU Xiangxing , Dept.of Mechanical Engineering , Tsinghua University , Beijing , 100084 , China

金属学报(英文版)

The cleavage fracture mechanism of granular bainitie weld metal in 15MnVN steel has been investigated.SEM observation of a special specimen for revealing simultaneously fracture sur- face and microstructure shows that the cleavage of the weld is initiated by M-A constituent. The 95th percentile equivalent diameter of M-A constituent controls the cleavage fracture stress of the weld metal.

关键词: granular bainite , null , null , null

Fractal Aggregation of Nonequilibrium Iodine

Jizhong ZHANG Xiaojun YANG Hengde LI Dept.of Materials Science and Engineering , Tsinghua University , Beijing , 100084 , China

材料科学技术（英文）

A large number of particles evaporated from liquid iodine deposited on the wall of a glass container. The deposits demonstrate three structural shapes:globule chain,network formation,and dendrite. The globule chain displays clearly self-similar feature,and can be characterized by fractal geometry. The fractal dimension of the globule chain patterns ranges from D=1.50 to 1.75.The in situ sublimat- ing process of an iodine fractal aggregate was observed.It revealed reversal of the random growth process under nonequilibrium condition.The analytical results show that the nucleation-aggregation (NA) model can explain the growth process of iodine fractal aggregate.

关键词: iodine , null , null

Relationship between Critical Hydrogen Concentration and Applied Stress for Hydrogen Induced Cracking in 0.2 wt—%C Annealed Plain Steel

ZHANG Baiyu , TANG Xiangyun Dept.of Materials Science and Engineering , Tsinghua University , Beijing , 100084 , China.

材料科学技术（英文）

关键词: hydrogen induced cracking , null , null , null

Microdeformation Behaviour of a Ferritic-Austenitic Duplex Stainless Steel

HE Jianhong TANG Xiangyun CHEN Nanping Department of Materials Science and Engineering Huazhong University of Science and Technology Wuhan , 430074 , China.Department of Materials Science and Engineering Qinghua University , Beijing , 100084 , China.

材料科学技术（英文）

Microdeformation of ferritic and austenitic grains in a ferritic-austenitic duplex stainless steel have been observed in-situ by SEM with photoetch. The plastic deformation behaviour of austenitic grains are similar to ferritic grains for hydrogen uncharged specimens,it follows Mileiko's strain-equal model.But it will be changed when the specimens are hydrogen charged.

关键词: microdeformation , null , null

Influence of Hydrogen on Dislocation Structure in a Duplex Stainless Steel

HE Jianhong TANG Xiangyun Department of Materials Science and Engineering Huazhong University of Science and Technology Wuhan , 430074 , China.Department of Materials Science and Engineering Qinghua University , Beijing , 100084 , China.

材料科学技术（英文）

The dislocation structure of specimens of a duplex stainless steel with precharged hydrogen has been investigated by transmission electron microscopy.The result showed the hydrogen acti- vated dislocation source on phase boundaries of ferrite/austenite and makes certain dislocations in austenite grains move.The dislocation appearances in each phase in specimens uncharged with hydrogen have been given for comparison.

关键词: duplex stainless steel , null , null