L.F. Li
,
Z.P. Chen
,
M.F. Jiang and W.Z. Wang(Department of Ferrous Metallurgy
,
School of Materials and Motallurgy
,
Northeastern University Shenyang 110006
,
China)(The Technology Center
,
Baoshan Iron & Steel Complex
,
Shanghai 201900
,
China)
金属学报(英文版)
The principle and steps for the calculation of component activities in fluxes using Schuhmann method are described. On the foris of Gibbs-Duhem equation and using Cr2O3 activities in BaO-BaF2-Cr2O3 system fiuxes, BaO activities at 1523 and 1673K are calculated, respectivelg,and the isoactivity diagrums of BaO are also obtained. The calculation results indicate that BaO activity increases with increasing its content in fiuxes, and decreaaes with the increase of Cr2O3 content at a given XBaO/XBaF2 ratio.
关键词:
Shuhmann method fluxes
,
null
,
null
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
Zhenya Zhang
材料科学技术（英）
This study investigated the microstructures and mechanical properties of ZK60 alloy prepared by a simplified rapid solidification powder metallurgy (RS P/M) processing system (S-RS P/M), which consists of warm press in dry air and hot extrusion. Microstructure characterizations showed that S-RS P/M alloy consisted of magnesium matrix and oxide stringers of ~1 μm in width. TEM (transmission electron microscopy) observations illustrated nano-size magnesia particles (10{30 nm) constituted oxide stringer in detail. Due to a relatively higher volume of nano-size magnesia particle produced during S-RS P/M process, 0.2% yield strength of S-RS P/M ZK60 alloy was found to be as high as 382 MPa, which is 10% higher than that of RS P/M alloy. The improvement in mechanical properties is mainly attributed to the combination effects of Orowan mechanism and coe±cient of thermal expansion (CTE) mismatch because of the approximately same average grain size.
关键词:
Microstructure
YANG Ying
,
YAN Qing-zhi
,
GE Chang-chun
钢铁研究学报(英文版)
Modified CNS-Ⅱ F/M steel was designed for in-core components of supercritical water cooled reactor. Study on the hot deformation behavior of modified CNS-Ⅱ F/M steel is of great importance for processing parameter planning and microstructure controlling during hot deformation. The hot deformation behavior of modified CNS-Ⅱ F/M steel was investigated through isothermal hot compression test at temperature ranging from 1223 to 1373 K and strain rate 001 to 10 s-1. The true stress-true strain data gained from compression tests were used to built constitutive equation of modified CNS-Ⅱ F/M steel. The influence of strain on the accuracy of constitutive analysis was incorporated, assuming strain has a influence on material constants. A 5th order polynominal equation with very good accuracy was used to represent the influence of strain on material constant. The flow stresses calculated from the constitutive equation were compared with test values in the whole experiment range and the absolute average error for the constitutive equation in predicting flow stress is 4728%. At last, the recrystallization behavior of modified CNS-Ⅱ F/M steel was investigated. The relationship of critical strain and peak strain with Zener-Hollomon parameter were given by an experimental equation.
关键词:
F/M steel
,
constitutive equation
,
dynamic recrystallization
ZHANG Xiumu LI Yiyi Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
In situ observations of the nucleation and growth of ferrous martensites,including ε-, lenticular,butterfly,thin-plate and composite-plate ones at low temperature stage on optical or transmission electron microscope were carried out.The results confirmed the faulting model for the formation of ε-martensite proposed by Olso and Cohen.The grain boundaries and tri- ple points are the favourable nucleation sites for the thin plates,and their surface relief grown initially like a small needle.The lenticular martensite was observed as two stages of formation.According to the dislocation resolving reaction. (a/6)[111]_b→(a/3)[]_b+(a/2)[111]_b,the emission dislocation(=(a/2)[111]_b)acting as the dislocation source for the transition of lattice invariant shear from twinning to slip was proposed.
关键词:
martensite
,
null
,
null
,
null
,
null
刘永
,
宋耀祖
工程热物理学报
本文采用M-Z干涉测量的方法,研究了半三角形翼片纵向涡发生器强化换热方案对矩形通道内气体流动换热的影响,获得了安装纵向涡发生器前后对流换热温度场的M-Z干涉图像.通过对实验获得的干涉图像进行分析处理,表明安装纵向涡发生器后,通道内入口段流动的热边界层明显变薄,反映了纵向涡对流动换热的强化作用,验证了将M-Z干涉测量方法应用于纵向涡强化换热研究的可行性.
关键词:
纵向涡
,
强化换热
,
M-Z干涉
,
热边界层
Electrochimica Acta
To investigate the corrosion protection mechanism of polyaniline (PANI) films on ferrous metals, this work presents preparation method of a separate protonated PANI film electrode and results of its open-circuit potential (OCP) in 0.5 M NaClO4 and 0.5 M Na2SO4 solutions with different pH and the galvanic interaction between the PANI film electrode and ferrous metals. X-ray photoelectron spectroscopy (XPS) shows the lower pH corresponds to higher protonation level of H+ in the film, and a more positive OCP of PANI film. The PANI film accelerated the corrosion of 20A carbon steel slightly with a PANI to steel area ratio less than 25: 1, while the PANI films maintained passivity for a ratio above to 25:1 for the 20A steel. For the coupling of 2Cr13 stainless steel/PANI, an equal area PANI film could maintain 2Cr13 in a passive state. The results suggest that corrosion protection of 20A carbon steel and 2Cr13 stainless steel by PANI film in the acid solution is due to passivity protection. The excess oxidative charge stored in the PANI and the equilibrium activity of protonated PANI with the acid environment provide a persistent driving force for carbon steel and 2Cr13 stainless steel passivity. (C) 2004 Elsevier Ltd. All rights reserved.
关键词:
protonated polyaniline;ferrous metals;open-circuit potential;galvanic;coupling;passivity;corrosion protection;mild-steel;coatings;behavior
