Jie FU
,
Shixiang ZHOU
,
Ping WANG
,
Lin DI
,
Jian ZHU
材料科学技术（英文）
The kinetics of denitrogenation from liquid steel was studied by using an oxygen-nitrogen analysis system(LECO TC-436) under 1600℃ similar to 2813℃ conditions. The results show that when [S]=0.005%, nitrogen removal was controlled by nitrogen transfer in liquid diffusion layer, when [S]=0.012% and 0.140%, it was controlled by both nitrogen transfer in liquid diffusion layer and the chemical reaction at the liquid-gas interface below 2250℃, and by nitrogen transfer in liquid diffusion layer under 2250℃ similar to 2813 degreesC conditions. The activation energy E-a was 57 kJ/mol for 0.0050%[S], 95 kJ/mol for 0.012%[S], 165 kJ/mol for 0.140%[S]. The resistance of sulphur on nitrogen removal decreased with the temperature rose, and disappeared at 2630℃. Based on the results obtained, it has been answered why the nitrogen in liquid steel can be decreased rapidly by carbon-oxygen reaction under very high oxygen and sulphur content conditions during the BOF, EAF, VOD and AOD steelmaking processes.
关键词:
Liang ZHANG
,
Xuesong LIU
,
Linsen WANG
,
Ping WANG
,
Hongyuan FANG
金属学报(英文版)
To investigate fatigue crack initiation characteristics of Al-Zn-Mg alloy welded joint, notched specimens were used in fatigue test for the base metal, welding bead and heat affected zone (HAZ). The fatigue fracture surface near the fatigue crack initiation site was observed by scanning electron microscope (SEM). The results show that the differences of fatigue crack initiation life among base metal, welding bead and HAZ are not obvious. Inhomogeneity in microstructure and mechanical performance of HAZ influences the fatigue crack initiation life. The ratio of fatigue crack initiation life (Ni) to fatigue failure life (N f)Al-Zn-Mg alloy|Welded joint|Fatigue crack initiation|Life prediction for the base metal, welding bead and HAZ of A7N01 aluminium alloy welded joint are 26.32%, 40.21% and 60.67%, respectively. Fatigue crack initiation life can be predicted using a uniform model. Observation of fatigue fracture surfaces shows that for the welding bead a fatigue crack initiates from the smooth surface due to the welding process, the blowhole in HAZ causes fatigue crack and the crushed second phase particles play an important role in fatigue crack initiation for the base metal.
关键词:
Al-Zn-Mg alloy
,
null
,
null
,
null
刘守平
,
周上祺
,
王佳眉
,
任勤
腐蚀学报（英文）
用金相显微镜、扫描电镜、X射线衍射仪和X射线能谱仪对天然气井油管悬挂器腐蚀失效进行了检测分析，并对天然气井油管悬挂器用35CrMo钢进行了盐雾试验，结果表明，天然气中的水和CO2是引起腐蚀的主要介质，腐蚀产物主要是FeCO3，高速天然气冲刷和钢中的非金属夹杂加剧了腐蚀的速度.
CORROSION FAILURE ANALYSIS OF AN OIL TUBE USED IN NATURAL GAS WELL
LIU Shou-ping,ZHOU Shang-qi,WANG Jia-mei,REN Qin
Chongqing University
A failed oil tube used in natural gas well was examined by optical microscope,scanning electron microscope ,X-ray diffractometer and X-ray spectrometer.Corrosion behavior of 35CrMo steel samples of the oil tube were investigated by means of salt spray tests in the laboratory.The results show that CO2 and H2O are primary factors in the corrosion of oil tube.The corrosion product is FeCO3,non-metallic inclusions in the steel and erosion of natural gas fluid played an important role in accelerating the corrosion.
oil tube;
natural gas well；
35CrMo steel；
failure analysis；
corrosion
关键词:
悬挂器
,
null
,
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
材料科学技术（英文）
The effect of interstitial hydrogen on the cohesion of the Al Sigma=11(113) grain boundary (GB) is investigated based on the thermodynamic model of Rice-Wang using the first-principles density function calculation. The results indicate that interstitial H behaves as an embrittler from "strengthening energy" analysis. The reduced GB cohesion due to the presence of H at the GB is attributed to the low affinity between H and Al, and the weakened bonding of Al atomic pairs perpendicular to GB plane.
关键词:
hydrogen;grain boundary;Al-Mg alloys;pseudopotentials;1st-principles
Xiaoguang LIU
,
Xiaowei WANG
材料科学技术（英文）
The effect of interstitial hydrogen on the cohesion of the Al ∑=11(113) grain boundary (GB) is investigated based on the thermodynamic model of Rice-Wang using the first-principles density function calculation. The results indicate that interstitial H behaves as an embrittler from "strengthening energy" analysis. The reduced GB cohesion due to the presence of H at the GB is attributed to the low affinity between H and Al, and the weakened bonding of Al atomic pairs perpendicular to GB plane.
关键词:
Hydrogen
,
null
,
null
Journal of Physics-Condensed Matter
This research purposes to investigate the atomic and electronic structures of the Al/TiC(001) interface with lattice misfit using the ab initio pseudopotential approach. A detailed analysis of the relaxed atomic structure reveals that the atoms over the initial unfavourable sites relax to the favourable sites along the lateral plane. The properties of the semicoherent interface can be taken as averages over the different coherent sites. In addition, the interface atoms in relatively favourable regions are dragged near to the interface, while those in unfavourable regions are pushed away from the interface. Therefore, a large war-ping near the interface is made perpendicular to the lateral plane. The calculated adhesions explain the different wetting results from the viewpoint of structural transition. The subsequent analysis of electronic properties demonstrates that adhesions dominate mainly via the strong Al-C covalent bond.
关键词:
first-principles;1st principles;adhesion;surfaces;misfit;1st-principles;wettability;al
X. Q. Yang
,
L. X. Huo
,
Y. F. Zhang and J. X. Yan (School of Material Science and Engineering
,
Tianjin University
,
Tianjin 300072
,
China)
金属学报(英文版)
The buckling formation and influence factors during welding thin - plated structures were investigated based on finite element methods, An engineering treatment method for prdicating the buckling distor- tion was proposed in here. It was used the equivalent applied thermal - load to simulate the welding residual stress,therefore the calculation of complex welding distoriton can be transformed into 3D elas- tic structural applied- load analyses, which can reduce the quantities of calculating works effectively. The validation of the method was verified by comparison of the numerical simulation and experimental results. The simulation of buckling distorition for side - walled structrues of paseenger train was per- formed and the calculation was in agreement with measuring results in general. It was shown that the main factors for producing the buckling were the intermittent fillet and ping the during welding the stiffened beams and columns to the panel.The existence of the free edge of panels would reduce the crit- ical buckling stress and enlarge the deflection obviously,but the continuous weld in closed frames didn' t degrade the buckling situation.
关键词:
welding buckling distortion
,
null
,
null
Physical Review B
By use of the linear-combination-of-atomic-orbital (LCAO) method for a cluster model, we studied the electronic structure of gamma-from Sigma 11 [1 (1) over bar0](11 (3) over bar) grain boundary doping with N and Mn atoms. The effect of the segregation on the cohesion of the grain boundary is investigated based on the Rice-Wang thermodynamic model. It is found that N could not only largely enhance the cohesion of the grain boundary but also eliminate the detrimental effect of Mn. The cosegregation effect of Mn and N on the cohesion of the grain boundary depends on where they segregate. Nitrogen could be reliably used in alloyed steels as an efficient strengthening element.
关键词:
electronic-structure;phosphorus segregation;stainless-steel;embrittlement;austenite;nitrogen;boron;impurities;fracture;metals
