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Carbides Evolution in 12Cr Martensitic Heat-resistant Steel with Life Depletion for Long-term Service

关键词:

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

C82DA和C92DA帘线钢的相变规律和组织对比

余万华 , 高山 , 刘飞 , 刘力哲 , 孙理 , 刘澄

材料热处理学报

对80级帘线钢C82DA和90级帘线钢C92DA化学成分进行检测,分析化学成分中合金元素差异对其相变的影响.采用光学显微镜、扫描电镜(SEM)、热膨胀仪和显微硬度仪,对比研究C82DA和C92DA的相变规律;相同热处理条件下的相变点、显微组织、珠光体片层间距;以及通过等温转变实验得到的相变动力学方程,并对参数n值和k值关系进行对比.结果表明:C92DA钢中的C、Si、Cr含量要高于C82DA,因此C92DA的片层间距要比C82DA细密,C92DA的n值要比C82DA大.这些结果对制定生产工艺和构建在线质量预报模型提供了基础数据.

关键词: 帘线钢 , 高碳钢 , 冷速 , 显微组织 , 相变模型

Influence of Phosphorus Microalloying on the Microstructure and Mechanical Properties of DA761 Superalloy

Materials Transactions

Effects of phosphorus microalloying on the microstructure and mechanical properties of direct-aging DA761 alloy have been studied. The aim of this work is to find a new way to develop a higher performance of wrought superalloy. The optimum addition of phosphorus in DA761 alloy is determined by investigating effects of phosphorus and boron on the microstructure and properties of DA761 alloy, that are compared to GH761 alloy treated by standard heat treatment. The stability of microstructure and properties of fine-grain DA761 alloy with optimum content of phosphorus is proved by studying the evolution of microstructure and properties of the alloy after long-term high temperature ageing. The practicability of phosphorus microalloying in improving the mechanical properties of DA761 alloy is verified by smelting a 500 kg ingot and detecting the microstructure and properties of billet near the size of engine disk. The results verify the phosphorus microalloying and fine-grain direct aging treatment in improving commercial GH761 alloy. Mechanism of phosphorus microalloying is also discussed. [doi: 10.2320/matertrans.MF200908]

关键词: phosphorus;GH761 alloy;fine-grain treatment;mechanical property;trace-elements

(da)/(dN)与K_1间关系的探讨

陈篪

金属学报

本文证明我们所建议的关系: (da/dN)-C[(△K)~2-K_2~2/K_1~2-(△K)~2]~p能够很好地表达R=(K_(min)/K_(max))=常数时(da/dN)随△K的全部变化,其中P值在1左右,C约在3×10~(-3)—10~(-2)毫米/周之间。

关键词:

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

Effect of carbon on DA718 alloy with P addition

材料科学技术（英文）

Lower content of carbon can further improve the stress rupture life of p-modified DA 718 alloy up to more than 270%. Meanwhile, the ductility of the alloy decreased a little. More boron atoms dissociate due to decreasing carbon content and interact with phosphorus which brings the longer stress rupture life of the alloy. Less carbon may induce more phosphorus segregating in the grain boundary and result in brittleness.

关键词: DA 718 alloy;carbon;phosphorus;phosphorus;segregation;superalloy

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

低能He2+与He原子碰撞转移电离出射电子能谱研究

冯文天 , 马新文 , 朱小龙 , 张少峰 , 刘惠萍 , 李斌 , 闫顺成

原子核物理评论

利用反应显微成像谱仪对70和100 keV He2+与He原子碰撞转移电离(TI)过程中不同出射角度的电子能谱进行了测量,观测到出射电子能谱具有如下分布特征:出射电子速度分布介于0和入射离子速度νp之间;在不同出射角度电子能谱分布均有一极大值存在,随着出射角度的增大,能谱分布极大值逐渐减小; 当电子出射角度等于45°时,多数电子集中在0 eV附近.上述特征可由低能离子-原子碰撞"准分子"模型进行定性解释.在100 keV He2+-He转移电离出射电子能谱中有靶电子被俘获至散射离子连续态(electron capture to continuum,简称ECC)电子的贡献,这可看做是动力学两步过程的作用.

关键词: 反应显微谱仪 , 转移电离 , ECC电子 , "准分子"模型

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