材料期刊网

TWO-DIMENSIONAL NUMERICAL ANALYSIS OF PLASMA IMMERSION ION IMPLANTATION OF CYLINDRICAL BORES

A. G. Liu , X.F. Wang , L.P. Wang , S. Y. Wang , B. Y. Tang and P.K. Chu 1) Advanced Welding Production Technology National Key Laboratory , HIT , Harbin 150001 , China 2) Department of Physics and Material Science , City University of Hong Kong , 83 Tat Chee Avenue , Kowloon , Hong Kang , China

金属学报(英文版)

Plasma immersion ion implantation (PIII), unrestricted by sight-light process, is considered a proper method for inner surface strengthening. Two-dimensional simulation oj inner surface PIII process of cylindrical bores were carried out in this paper using cold plasma fluid model, and influence of the bore's dimension on impact energy, retained dose and uniformity of inner surface were investigated.

关键词: plasma immersion ion implantation , null , null , null

ION HEATING PROCESS DURING PLASMA IMMERSION ION IMPLANTATION

X.B. Tian , X.F. Wang , A.G. Liu , L.P. Wang , S. Y. Wang , B. Y. Tang and P. K. Chu 1)Advanced Welding Production & Technology National Key Laboratory , Harbin Institute of Technology , Harbin 150001 , China 2)Department of Physics & Materials Science , City University of Hong Kong , China

金属学报(英文版)

The research on plasma immersion ion implantation has been conducted for a little over ten years. Much is needed to investigate including processing technlogy, plasma sheath dynamics, interaction of plasma and surface, etc. Of the processing methods elavated temperature technique is usually used in PIII to produce a thick modified layer by means of the thermal diffusion. Meanwhile plasma ion heating is more recently developed by Ronghua Wei et al[1]. Therefore the temeperature is a critical parameter in plasma ion processing. In this paper we present the theoretical model and analysize the effect of imlantation voltage, plasma density, ion mass,etc on the temperature rise.

关键词: plasma immersion ion implantation , null , null

Capacitance of High-Voltage Coaxial Cable in Plasma Immersion Ion Implantation

X.B. Tian , L.P. Wang , D. T.K.Kwok , B. Y Tang , P.K.Chu

材料科学技术（英）

Plasma immersion ion implantation (PIII) is an excellent technique for the surf see modification of complex-shaped components. Owing to pulsed operation mode of the high voltage and large slew rate, the capacitance on the high-voltage coaxial cable can be detrimental to the process and cannot be ignored. In fact, a significant portion of the rise-time/fall-time of the implantation voltage pulse and big initial current can be attributed to the coaxial cable.

关键词:

Modeling Of `Banding' Microstructure Formation In Centrifugally Solidified Ti-6al-4v Alloy

D.R. Liu , E.J. Guo , L.P. Wang

金属学报(英文版)

Numerical investigations of the `banding' microstructure formation during solidification of Ti-6Al-4V alloy in the centrifugal casting are conducted using a multi-scale model, which combines the finite difference method (FDM) at the macroscale with a cellular automaton (CA) model at the microscale. The macro model is used to simulate the fluid flow and heat transfer throughout the casting. The micro model is used to predict the nucleation and growth of microstructures. With the proposed model, numerical simulations are performed to study the influences of the nucleation density, mould rotation speed, and casting size upon the banding' microstructure formation. It is noted that changing the nucleation density has a minor effect on the microstructure formation. The rotation speed promotes the formation of `banding' microstructure, which is more noticeable for larger size castings.The major mechanism responsible for this `banding' phenomenon is thespatial variation in cooling rates created by centrifugal force.

关键词: Modeling , null , null

Two-step magnetization in a spin-chain system on the triangular lattice: Wang-Landau simulation

Physical Review B

The Wang-Landau algorithm is used to study the thermodynamic and magnetic properties of triangular spin-chain system based on two-dimensional Ising model in order to understand the magnetic-order dynamics in Ca(3)Co(2)O(6) compound. The calculated results demonstrate that the equilibrium state of the rigid spins produces the two-step magnetization curve at low temperature even when the random-exchange term is considered. This work indicates that the four-step magnetization behavior observed experimentally must be due to the nonequilibrium magnetization.

关键词: calcium compounds;exchange interactions (electron);Ising model;magnetisation;thermodynamics;one-dimensional ca3co2o6;density-of-states;compound ca3co2o6;phase-diagram;proteins;crystal

P510L钒微合金化钢的CCT曲线及其显微组织

刘健 , 张开坚 , 陆建生 , 左军 , 杨峰 , 孙建阁

上海金属 doi:10.3969/j.issn.1001-7208.2009.01.005

通过测定P510L钢在不同冷速下的连续冷却转变的膨胀曲线,获得了该钢的CCT曲线;研究了P510L钢连续冷却过程中奥氏体的转变过程及转变产物的组织形态和显微组织,通过对CCT曲线的分析为控轧控冷工艺提供理论依据.

关键词: P510L钢 , CCT曲线 , 显微组织 , 显微硬度

FeMoB Enhanced Sintering of P/M 316L Stainless Steel

YANG Xia , GUO Shiju

钢铁研究学报(英文版)

Liquidphase enhanced sintering of powder metallurgy (P/M) 316L stainless steel by addition of sintering aids was studied. 2%-8% of prealloyed FeMoB powder with two different particle sizes was added as sintering aids, and the specimens were sintered in vacuum at 1 200-1 350 ℃. The results show that the fine FeMoB powder (5-10 μm) has stronger activated effect. The sintered density increases with the increase in sintering aid content or sintering temperature. Warm compaction has a better effect on the control of dimensional precision of compacts. The prealloyed FeMoB powder deviated from Mo2FeB2 component can also be sintering aid of P/M 316L stainless steel.

关键词: P/M 316L stainless steel;liquidphase sintering;activated sintering;FeMoB;sintering aid

P510L钒微合金化钢连续冷却转变特征

余万华 , 周李泉 , 韩静涛 , 张中平 , 刘勇 , 佘广夫

钢铁钒钛 doi:10.3969/j.issn.1004-7638.2006.03.011

采用膨胀法测定了攀枝花新钢钒热轧板厂的高强度P510L钒微合金化钢的CCT曲线,采用金相显微镜分析不同冷速下的显微组织.分析发现,冷却速度较慢(低于10℃/s)时,得到的显微组织为比较粗大的铁素体+珠光体组织;中速冷却时,组织为比较细小均匀的铁素体+珠光体组织;快冷时(高于35℃/s)主要为贝氏体和铁素体组织.进一步采用扫描电镜分析P510L显微组织,发现大量钒的析出物,V(CN)析出物的形态为从球形至长方形,其大小为10～30 nm.

关键词: 微合金钢 , 热轧 , 显微组织 , CCT曲线

腐蚀介质温度对316L/Ni-P镀层腐蚀及电化学行为影响

方信贤 , 巴志新 , 甄睿 , 王章忠

材料热处理学报

采用质量损失法研究了化学镀Ni-P镀层及对比材料316L在单相流(20％ H2SO4)和两相流(20％ H2SO4+ 20 g/L黄砂)中冲刷腐蚀行为,以及电化学方法研究了介质温度对Ni-P镀层及316L电化学行为的影响.结果表明,介质温度升高(20 ～80℃),Ni-P镀层腐蚀速率、冲刷腐蚀速率和冲刷腐蚀交互作用增大,但与316L和300℃热处理的晶态镍磷镀层相比,介质温度对镀态和200 ℃热处理的非晶镍磷镀层影响较小.镀态镍磷和316L的腐蚀电流密度随介质温度升高而增大,容抗弧半径则随介质温度升高而减小.Ni-P镀层腐蚀和单相流冲刷腐蚀机制是均匀腐蚀,而两相流中则为均匀腐蚀+犁削机制.

关键词: Ni-P镀层 , 316L , 腐蚀 , 冲刷腐蚀 , 阻抗谱

Ion sputter erosion in metallic glass-A response to "Comment on: Homogeneity of Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass" by L-Y. Chen, Y-W. Zeng, Q-P. Cao, B-J. Park, Y-M. Chen, K. Hono, U. Vainio, Z-L. Zhang, U. Kaiser, X-D. Wang, and J-Z Jiang J. Mater. Res. 24, 3116 (2009)

Journal of Materials Research

The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.

关键词: room-temperature