材料期刊网

THERMAL FATIGUE CRACKING IN STEEL 5CrMnMo

HE Shiyu LI Ying LIU Jianhong Harbin Institute of Technology , Harbin , China HE Shiyu , Faculty of Metal , Harbin Institute of Technology , Harbin , 150006 , China

金属学报(英文版)

The thermal fatigue behaviour of steel 5CrMnMo after various heat treatments has been examined by means of Coffin-model and self-strained thermal fatigue testing machines.The thermal fatigue crack initiation and propagation have been observed under SEM and TEM. The majority of thermal fatigue cracks of the quenched samples initiated firstly at the grain boundaries and that of the quenched-tempered samples at the breakage interface of the car- bide and matrix.The thermal fatigue cracks of either quenched or quenched-tempered steel propagated mainly along the breakage interface of carbide and grain boundaries.

关键词: thermal fatigue crack , 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）

关键词: steel , null , null

Formation of PFZ and Its Effect in a RSP AI-Li Alloy

Liang ZHEN Yuexian CUI Dezhuang YANG Department of Materials Science , Harbin Institute of Technology , Harbin , 150006 , ChinaShenglong DAI Guifu YU Beijing Institute of Aeronautical Materials , Beijing 100095 , China

材料科学技术（英）

The formation of precipitation free zone (PFZ) and its effect in a RSP AI-Li alloy has been studied. The results show that PFZ is easy to form when aged at 190℃,but there is no equilibrium phase on grain boundaries.The growth of PFZ in the alloy is different from that in conventional AI-Li alloys, The effect of PFZ is of great importance because of its large volume fraction in the alloy.It offsets the beneficial effect of RSP,and is thought to be an important factor that leads to the poor toughness and low ductility of RSP AI-Li alloy sheet.

关键词: precipitation free zone , null , null , null

Laser Surface Modification of Ti-6Al-4V with Addition of Pr

CHE Chengwei ZHANG Zhiming DONG Xianglin LIU Chengliang Harbin Institute of Technology , Harbin , 150006 , ChinaInstitute of Metal Research , Academia Sinica Shenyang , 110015 , China

材料科学技术（英）

The behaviour of oxidation at elevated tem- peratures and fretting in the laser-alloyed layer of Ti-6Al-4V with the addition of Pr was studied. The results show that the addition of Pr changes the structure of oxide scale of Ti-6Al-4V,controls the short-range diffusion of oxygen to the scale/substrate interface and increases the adhe- sion and ductility of the scale,thus changing the oxidation kinetics and considerably reducing oxidation rate.The analysis of fretting test shows that the existence of high hardness layer in the al- loyed zone,fine dendrites perpendicular to the sur- face of the high hardness layer and the oxide scale produced during fretting at elevated temperatures are all beneficial to the improvement of wear resist- ance.

关键词: laser modification , null , null , null

Extrusion Deformation Texture of SiC_W/Al Composites

JIAO Chengge YAO Zhongkai HAN Yafang Beijing Institute of Aeronautical Materials , Beijing , 100095 , ChinaHarbin Institute of Technology , Harbin , 150006 , China

材料科学技术（英）

The interface orientation relationships between SiC whiskers and matrix have been studied by X-ray diffraction and crystallite orientation distri- bution functions (CODFs) analysis.The distribu- tion of SiC whiskers in Al matrix of the as-cast SiC_w/Al composite was nearly unperfect isotropic. Both matrix and SiC whisker in as-extruded SiC_w/Al composite were〈111〉fiber texture.It is suggested that there are certain interface orientation relationships between the SiC_w and the Al matrix.

关键词: texture , null , null

Molecular Dynamics Simulation of Liquid Noble Metals Au and Ag

LI Qingchun CHEN Kuiying ** Dept.of Metals and Technology , Harbin Institute of Technology , Harbin , 150006 , China+ To whom correspondence should be addressed

材料科学技术（英）

关键词: molecular dynamics simulation , null , null

Modulated Structures in 10Ni and 18Ni Maraging Steels

YIN Zhongda LI Xiaodong ZHENG Mingzhe CHE Jianying ** Department of Metals and Technology , Harbin Institute of Technology , Harbin , 150006 , ChinaTo whom correspondence should be addressed.

材料科学技术（英）

关键词: modulated structure , null , null

Fatigue Crack Propagation in Plain Carbon Dual-phase Steel

LEI Tingquan LIN Guangyong ** Dept.of Metals and Technology , Harbin Institute of Technology , Harbin , 150006 , China+ To whom correspondence should be addressed

材料科学技术（英）

The effect of volume fraction V_M and carbon content(%C)_M of martensite was studied on the fa- tigue crack propagation behaviour of plain carbon martensite plus ferrite M+F dual-phase steel.The experimental results show that the △K_(th)decreases and da/dn increases with increasing V_M and (%C)_M at a load ratio R=0.05.High△K_(th)values are obtained by obvious crack closing ability caused by high roughness of the fractured surfaces.

关键词: fatigue crack propagation , null , null

Development of Some Fundamental Research of SiC_W/Al Composites in HIT PartⅠ Microstructure and SiC/Al Interface of SiC_W/Al Composites

Lin GENG Congkai YAO Dept.of Metals and Technology , Harbin Institute of Technology (HIT) , Harbin , 150006 , China

材料科学技术（英）

The microstructure of SiC whisker reinforced aluminium alloy (SiC_w/Al) composite is reviewed,and the SiC-Al interface in SiC_w/Al composite is especially discussed,The main contents are morphology of the aluminium matrix in SiC_w/Al composite;microstructures and defects of SiC whiskers in SiC_w/Al composite and bonding mechanisms of the SiC-Al interface in SiC_w/Al com- posite.

关键词: silicon carbide , null , null , null , null

FEM Simulation of the Hydroforming Process of Spherical Vessels from Combination Frustum Shells

Shihong ZHANG Zhongren WANG (Z.R. Wang) Yingchun GUO Jianyi WANG Dept.of Materials Science and Technology.Harbin Institute of Technology , Harbin , 150006 , China

材料科学技术（英）

The dieless hydroforming of spherical vessels from combination frustum shells is put forward in the present paper,and the forming process is developed by means of elastoplastic finite element method and experiments.In this paper the principle and experimental procedure of the new technology are introduced,the simulation method and the calculating assumptions are presented,the deformation process and the deformation characteristics of the shells are discussed,as well as the stress and strain distributions of the shell during bulging are analysed.

关键词: spherical vessel , null , null , null