SU Zuwu MENG Guowen GUO Hongzhen LIU Jianchao YAO Zekun Northwestern Polytechnical University
,
Xi'an
,
ChinaYANG Zhaosu HU Zongshi Baoji Non-Ferrous Metals Mill
,
Baoji
,
China
金属学报(英文版)
The formation reason and elimination method of non-uniform microstructure defects in Ti al- loy TC11 bar have been studied.The coagulating and coarsening into block of the part of grain boundary α and secondary α seem to be caused by the ingot cogging and initial forging temperature in the β region as well as no more enough deformation and uneven distribution. The grain α,elongated α and blocky α may be finally eliminated by adopting the technique of (α+β)thermomechanical processing+β processing,W.Q.+recrystallization annealing,A.C., thus the size of uniform and fine equiaxed α structure is believed to be reduced to 1.9258μm.
关键词:
TC11 Ti alloy
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null
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null
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null
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
Materials and Corrosion-Werkstoffe Und Korrosion
In order to investigate the galvanic anodic protection (GAP) of ferrous metals (such as 410, 304 and 316 stainless steels) in acid solutions by doped polyaniline (PANi), separate doped PANi powder-pressed electrodes with different surface areas (the area ratio of the PANi electrode to stainless steel is between 1:1 and 1:2) have been prepared. These were coupled with ferrous metal in the following solutions: 5 M sulphuric acid, 5 M phosphoric acid and industrial phosphoric acid (containing 5 M phosphoric acid and 0.05% chloride ion) to construct a galvanic cell, in which PANi is cathode while ferrous metal is anode. The results indicate that a PANi electrode with sufficient area can provide corrosion protection to stainless steel in these acidic solutions. A pilot scale coupling experiment was carried out. The results indicate that PANi is a promising material as an electrode for the anodic protection of ferrous metals in acidic solutions in industrial situations.
关键词:
conducting polymer-coatings;corrosion protection;stainless-steel;spectroscopy;passivation;performance;mechanism;behavior;primers;films
Acta Materialia
In a first report [Jin ZH.. Gumbsch P, Ma E, Albe K, Lu K, Hahn H, et al. Scripta Mater 2006;54:1163], interactions between screw dislocation and coherent twin boundary (CTB) were studied via molecular dynamics simulations for three face-centered cubic (fcc) metals, Cu, Ni and Al. To complement those preliminary results, purely stress-driven interactions between 60 degrees non-screw lattice dislocation and CTB are considered in this paper. Depending on the material and the applied strain, slip has been observed to interact with the boundary in different ways. If a 60 degrees dislocation is forced by an external stress into a CTB, it dissociates into different partial dislocations gliding into the twin as well as along the twin boundary. A sessile dislocation lock may be generated at the CTB if the transited slip is incomplete. The details of the interaction are controlled by the material-dependent energy barriers for the formation of Shockley partial dislocations from the site where the lattice dislocation impinges upon the boundary. (c) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
关键词:
dislocation;slip;twinning;twin grain boundary;molecular dynamics;molecular-dynamics simulation;grain-boundaries;nanocrystalline;materials;cross-slip;rate sensitivity;deformation;copper;strength;aluminum;fcc
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
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null
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null
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null
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null
LIU Chengjun
,
SHI Peiyang
,
ZHANG Dayong
,
JIANG Maofa
钢铁研究学报(英文版)
A great amount of ferrous tailings and slag cause severe damage to the ecological environment, which must be reclaimed and utilized. The composition, type, and characteristics of ferrous tailings and slag in China were introduced. The research status and the application outlook of glass ceramics made from ferrous tailings and slag were discussed. Glass ceramics made from ferrous tailings and slag can be applied to various fields, and it will be environmentally conscious materials in the 21st century.
关键词:
glass ceramics;ferrous tailings;slag
XIA Zhenhai Hebei Institute of Technology
,
Tianjin
,
ChinaMAO Zhiying ZHOU Yaohe Northwestern Polytechnical University
,
Xi'an
,
China Doctor
,
Faculty of Foundry
,
Department of Mechanical Engineering No.2
,
Hebei Institute of Technology
,
Tianjin 300132
,
China
金属学报(英文版)
On the basis of fluid kinetics,a model for infiltration kinetics of liquid metals into fibre pre- fabricated composite has been proposed.The infiltration processing,together with the measurements of infiltrating velocity and permeability,for the C fibre-reinforced Al matrix composites have been studied.The model proposed seems to be in good agreement with the ex- perimental results.Two different infiltration modes,uniform and non-uniform,were found and a new technique was suggested.Thus,the quality composites of C fibre-reinforced Al may be made under low pressure regardless of non-wettability of liquid metal to the fibres.
关键词:
liquid metal
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null
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null
ZHANG Yun-hua
,
et al
钢铁研究学报(英文版)
A large amount of oily wastewater is discharged during steel rolling in the steel industry, and the emulsion wastewater discharged during the steel cold-rolling mill contain a lot of non-degradable organic pollutants. However, the traditional treatments of oily wastewater can hardly work well to reach the discharge standards. There are two new techniques for emulsification wastewater treatment: the one is the integrated process of gas-energy-flocculation (GEF) and electrochemical catalytic oxidation (ECO) and membrane bioreactor (MBR); the other is the integrated process of ultra-filtration (UF) and ECO and MBR. Both of them are adopted to the continuous pilot test on the scale of 200L/h to 3000L/h. Moreover, every module of the combined techniques is analyzed. The operating parameters of every mould are investigated and the relationships between the operating parameters and CODCr removal efficiencies of the two integrated processes are evaluated. The experimental results have shown that almost all the oil and non-degradable organic substances are effectively removed with the effluent CODCr less than 30mg/L. The ultimate treated water quality could meet the requirement for productive reuse. What’s more, the integrated process of UF and ECO and MBR has a more stable effluent quality. Hence it can be widely used in a variety of industrial fields.
关键词:
cold rolling emulsion wastewater;gas-energy-management
HU Chang-qing
,
HAN Tao
,
ZHANG Yu-zhu
,
ZHANG Zhi-xia
钢铁研究学报(英文版)
For the recycling of ferrous sludge from steel industry, the carbonation pellet process should be considered as a “green” process, since no impurities are added as well as CO2 can be sequestrated and consumed. Through the thermodynamic calculation, the carbonation reaction can occur spontaneously and is an exothermic reaction. Based on the kinetic analysis through unreacted core model, the interfacial chemical reaction was the rate controlling step in the initial fast stage of carbonation, and the CO2 diffusion through the CaCO3 product layer was the rate controlling step in the following extremely slow stage. For the carbonation bonded mechanism, the pellet strength was gained by the formation and growing of CaCO3 product layer. Since the interfacial chemical reaction was the critical stage of the entire carbonation process, the emphasizes should be focused on the improvement of sorbent activity and the optimization of process parameters, such as pore structure, pore surface area, and total pressure, CO2 partial pressure, reaction temperature, etc to accelerate the reaction rate and to improve the quality of carbonation pellets.
关键词:
CO2 sequestration
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ferrous sludge
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carbonation pellet
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thermodynamics
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kinetics
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unreacted core model
