材料期刊网

Prediction Models on Distribution of Inherent Strains in T Type Welding Structure

Peng HE , Jicai FENG , Jiecai HAN , Yiyu QIAN

材料科学技术（英）

A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. The method of predicting maximum hardness Hv(y, z) and maximum inherent strain gmax is given. The model T.E.P-Tav-hardness calculation is proposed to predict distribution of inherent strains in T type welding structure. By T.E.P-Tav-hardness calculation, distribution of longitudinal inherent strains can be predicted in T type welding structure, and calculation and experimental results are consistent.

关键词: Inherent strain , null , null

Characteristics and Mechanism of Reduction and Smelting-separation Process of Copper Slag

Jun ZHANG , Yuan-hong QI , Ding-liu YAN , Xiang-li CHENG , Peng HE

钢铁研究

关键词:

Distribution of longitudinal inherent strains in multiple-passes welding

Peng HE , Jiuhai ZHANG , Toshio Terasake , Testuya Aliyama

材料科学技术（英）

A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. The computing method of distribution of longitudinal inherent strains in multiple-passes welding in heavy plate weldment is proposed. Distribution of longitudinal inherent strains in one-pass welding and two-passes welding are compared and analyzed. The effect of cutting on inherent strain is discussed.

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Distribution of inherent strains and residual stresses in medium thickness plate weldment

Peng HE , Jiuhai ZHANG , Toshio Terasaki , Testuya Akiyama

材料科学技术（英）

A fundamental theory for the analysis of residual welding stresses and deformation based on the inherent strain distribution along the welded joint is introduced. Distribution of inherent strains and longitudinal residual stresses in medium thickness plate weldment is calculated and analyzed. A new method of calculating inherent strains and longitudinal residual stresses is proposed.

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Microstructure and Strength of Brazed Joints of Ti3Al Base Alloy with Cu-P Filler Metal

Peng HE , Jicai FENG , Heng ZHOU

材料科学技术（英）

Brazing of Ti3Al alloys with the filler metal Cu-P was carried out at 1173~1273 K for 60~1800 s. When products are brazed, the optimum brazing parameters are as follows: brazing temperature is 1215~1225 K; brazing time is 250~300 s. Four kinds of reaction products were observed during the brazing of Ti3Al alloys with the filler metal Cu-P, i.e., Ti3Al phase with a small quantity of Cu (Ti3Al(Cu)) formed close to the Ti3Al alloy; the TiCu intermetallic compounds layer and the Cu3P intermetallic compounds layer formed between Ti3Al(Cu) and the filler metal, and a Cu-base solid solution formed with the dispersed Cu3P in the middle of the joint. The interfacial structure of brazed Ti3Al alloys joints with the filler metal Cu-P is Ti3Al/Ti3Al(Cu)/TiCu/Cu3P/Cu solid solution (Cu3P)/Cu3P/TiCu/Ti3Al(Cu)/Ti3Al, and this structure will not change with brazing time once it forms. The thickness of TiCu+Cu3P intermetallic compounds increases with brazing time according to a parabolic law. The activation energy Q and the growth velocity K0 of reaction layer TiCu+Cu3P in the brazed joints of Ti3Al alloys with the filler metal Cu-P are 286 kJ/mol and 0.0821 m2/s, respectively, and growth formula was y2=0.0821exp(-34421.59/T)t. Careful control of the growth for the reaction layer TiCu+Cu3P can influence the final joint strength. The formation of the intermetallic compounds TiCu+Cu3P results in embrittlement of the joint and poor joint properties. The Cu-P filler metal is not fit for obtaining a high-quality joint of Ti3Al brazed.

关键词: Brazed joints , null , null

卤代烃的Peng-Robinson状态方程的密度修正

林鸿 , 段远源

工程热物理学报

利用密度平移的方法对Peng-Robinson状态方程计算的液相密度进行了修正,给出了其描述平移量的关联式.对22种卤代烃纯物质的计算结果表明,修正后的PR方程能够很好地计算液相密度,并且能很好地再现纯物质的临界压缩因子,计算精度可以满足工程应用的需要.

关键词: PR状态方程 , 密度漂移 , 卤代烃 , 临界压缩因子

THERMAL NUCLEATION AND GROWTH OF He BUBBLES IN He IMPLANTED STAINLESS STEELS

ZHANG Lei WANG Peixuan TAO Rong MA Ruzhang ZHANG Guoguang University of Science and Technology Beijing , Beijing , China professor , Department of Materials Physics.University of Science and Technology Beijing.Beijing 100083 , China

金属学报(英文版)

Nucleation and growth of He bubbles at different annealing temperatures T≤1023 K in stain- less steels HR-2 and SS321,implanted with He~+(40-70 keV.1×10~(16)-6× 10~(17) He~+/cm~2),were ohserved under TEM.T=0.45T_m seems to be a transition temperature.The He bubbles continue mainly their nucleation at 0.3T_m< T<0.45T_m,and grow predominantly at T≥0.45T_m,due probably to migration and coalescence by surface diffusion of metal atoms around the bubbles.The apparent activation energies for the growth are found to he 0.41 and 0.31 eV for HR-2 and SS321 respectively.The bubble density in HR-2 is greater than that in SS321 within whole measuring temperature range,and the onset temperature of rapid swelling is also higher.It is believed that the resistance of HR-2 to He is superior to that fo SS321.

关键词: stainless steel , null , null , null , null

高温退火后含He纳米晶钛膜中He相关缺陷的演化

李悦 , 邓爱红 , 刘莉 , 王康 , 谢莎

材料研究学报

利用x射线衍射(xRD)和慢正电子束分析(SPBA)技术研究高温退火后含He钛膜的微观结构和钛膜内He相关缺陷的演化.XRD分析表明,高温退火后Ti和Si在高温下发生反应形成稳定的多晶TiSi2化合物,He原子的掺入会影响TiSi2晶体的择优取向,而对TiSi2晶粒尺寸的影响较小.SPBA结果表明,室温下,钛膜内的缺陷浓度或尺寸会随着掺He浓度的增加而增大;高温退火后,当He浓度小于5％(原子分数,下同)时(除2％外),钛膜内的He相关缺陷浓度随着He浓度增加相应地增加.当He浓度增加到14％时,高温会使较高浓度的He原子、He-空位复合体以及小He泡迁移聚集形成一些尺寸较大He泡,而较大He泡周围与He相关的小尺寸缺陷的浓度则会发生相应地减少.

关键词: 金属材料 , 含He钛膜 , 直流磁控溅射 , He相关缺陷 , XRD , SPBA

直流磁控溅射沉积含He钛膜的研究

施立群 , 金钦华 , 刘超卓 , 徐世林 , 周筑颖

原子核物理评论 doi:10.3969/j.issn.1007-4627.2005.01.045

研究了用He/Ar混合溅射气体的直流磁控溅射制备钛膜中He的掺入现象.分析结果表明,大量的He原子(He/Ti原子比高达56%) 被均匀地引入到Ti膜中,He含量可由混合溅射气体的He分量精确控制.通过调节溅射参数,可实现样品中He的低损伤引入.研究还发现,溅射沉积的含氦Ti膜具有较高的He成泡剂量和高的固He能力,这可能是溅射沉积形成了纳米晶Ti膜所致.纳米晶Ti膜较粗晶材料具有很高浓度的He捕陷中心,使He泡密度增大而泡尺寸减小.随He引入量的增加,Ti膜的晶粒尺寸减小,He引起的晶体点阵参数和X射线衍射峰宽度增大,晶体的无序程度增加.

关键词: 氦 , 损伤 , 泡 , 钛膜 , 溅射沉积

Heuristic treatments of tricritical behaviour as observed in 4He-3He mixtures and in polymeric assemblies

Physics and Chemistry of Liquids

Tricritical behaviour in three dimensions is accessible to experiment in, for example, 4He-3He mixtures and some polymeric assemblies. Here, by largely heuristic arguments, which appeal however to some specific model Hamiltonians, we indicate how one can understand the gist of the experimental results near the tricritical point in the systems cited above. We point out that the spin fluctuations at the tricritical point are much weaker than those at the critical point, which leads to the conclusion that the tricritical behaviours can be described well by the mean-field exponents with logarithmic corrections, at d = 3.

关键词: tricritical behaviour;tricritical exponents;4He-3He mixtures;polymeric assemblies;Ising model;emery-griffiths model;single-ion-anisotropy;ising-model;phase-separation;magnetic-properties;lattice statistics;crystal-field;exponents;superconductivity;transition