H. Lei
,
M. Y. Zhu and J.C. He (School of Materials and Metallurgy
,
Northeastern University
,
Shenyang 110006
,
China)
金属学报(英文版)
The study on the fluid flow, meniscus oscillation, slag entrapment in continuous casting mould was conducted mathematically and experimentally. The results show that the injection of argon into submerged nozzle enhances the meniscus oscillation, thus increases the probability of slag entrapment, and the critical argon blowing flow rate, which will give rise to slag entrapment, is around 10l/min. The trajectory of bubble is affected by the bubble diameter and the molten steel flow, and the bubble diameter is dominant. The bubble with diameter 1.4mm floats fastest with 0.47m/s terminal velocity.
关键词:
continuous casting mould
,
null
,
null
,
null
,
null
向鑫陈长安刘柯钊罗丽珠刘婷婷王小英
金属学报
doi:DOI:10.3724/SP.J.1037.2009.00590
用离子注入技术实现了Al表面C元素的掺杂, 并利用XPS, XRD, TEM和SEM研究了C掺杂对Al中离子
注入He行为的影响. 结果表明, 掺杂的C在Al表面形成了Al4C3, 随着C掺杂量的增加, Al表面组织的择优取向
和晶胞体积发生改变, 从而影响了Al中的He离子注入行为. 预先掺杂的C对He离子注入Al表面的鼓泡行为有重
要影响, 其影响程度与掺杂剂量有关. 小剂量C掺杂后, 能有效抑制鼓泡的长大, 并使Al表面鼓泡均匀分布; 更高
剂量C掺杂后, C对表面鼓泡的抑制作用减弱, 甚至加剧He离子的辐照损伤, Al表面出现孔洞和剥落现象. 掺杂的
C对Al基体的微观结构也有很大影响.
关键词:
Al
,
C doping
,
He behavior
,
blistering
,
microstructure
向鑫
,
陈长安
,
刘柯钊
,
罗丽珠
,
刘婷婷
,
王小英
金属学报
doi:10.3724/SP.J.1037.2009.00590
用离子注入技术实现了Al表面C元素的掺杂,并利用XPS,XRD,TEM和SEM研究了C掺杂对Al中离子注入He行为的影响.结果表明,掺杂的C在Al表面形成了Al_4C_3,随着C掺杂量的增加,Al表面组织的择优取向和晶胞体积发生改变,从而影响了Al中的He离子注入行为,预先掺杂的C对He离子注入Al表面的鼓泡行为有重要影响,其影响程度与掺杂剂量有关,小剂量C掺杂后,能有效抑制鼓泡的长大,并使Al表面鼓泡均匀分布;更高剂量C掺杂后,C对表面鼓泡的抑制作用减弱,甚至加剧He离子的辐照损伤,Al表面出现孔洞和剥落现象,掺杂的C对Al基体的微观结构也有很大影响,
关键词:
Al
,
C掺杂
,
He行为
,
鼓泡
,
微观结构
GUO Jin-hua
,
GAO Zhen
,
NI Xiao-jun
,
et al
钢铁研究学报(英文版)
Fe55Ni2Cr12Mo10B6C13Y2，Fe55Cu2Cr12Mo10B6C13Y2 and Fe55Nb2Cr12Mo10B6C13Y2 alloys with diameter of 4mm were produced by copper mold casting. The role of alloying additions (Ni, Cu or Nb) on corrosion resistance of Fe55Nb2Cr12Mo10B6C13Y2, Fe55Ni2Cr12Mo10B6C13Y2 and Fe55Cu2Cr12Mo10B6C13Y2 alloys were studied by polarization curves and electrochemical impedance spectroscopy (EIS). The results show that Fe55Ni2Cr12Mo10B6C13Y2 and Fe55Cu2Cr12Mo10B6C13Y2 alloys can be cast into bulk metallic glasses. Fe55Ni2Cr12Mo10B6C13Y2 and Fe55Cu2Cr12Mo10B6C13Y2 amorphous alloys with passive potential about 1500 mV exhibit good corrosion resistance in 5 % NaCl solution and 1 mol/L HCl solution. The passive current density of the alloy with Ni addition is lower than other alloys. EIS results only show one impedance element. Amorphous alloy Fe55Ni2Cr12Mo10B6C13Y2 with larger charge transfer reaction resistance indicates good corrosion resistance.
关键词:
amorphous;polarization curve;electrochemical impedance spectroscopy
材料科学技术（英文）
The corrosion of an Fe-based alloy containing 15 wt pet Y in H-2-H2S mixtures under 10(-3) Pa S-2 was studied at 600 similar to 800 degrees C in an attempt to find materials with improved sulphidation resistance with respect to pure Fe. The presence of Y has been shown to be beneficial, but not sufficient to the level expected. In fact, the alloy is able to form at all tested temperatures an external FeS layer, beneath which a zone containing a mixture of the two sulphides is also present. Thus, Fe can still diffuse through this region to form the outer FeS layer with non-negligible rate. The corrosion rate of Fe is considerably reduced by the Y addition, but the alloy corrodes still much more rapidly than Y. The sulphidation kinetics is generally rather irregular for both the pure metals, while the corrosion rate of the alloy decreases with time and tends to become parabolic after an initial period of 12 similar to 17 h. The sulphidation behaviour of the alloys is discussed by taking into account the presence of an intermetallic compound Fe17Y2 and the limited solubility of Y in Fe.
关键词:
high-temperature sulfidation;most-reactive component;ni-nb alloys;h2-h2s mixtures;behavior;600-degrees-c-800-degrees-c;oxidation
Y.G. Cao
,
X.Y. Sun
金属学报(英文版)
J-integral and crack opening displacement δ(COD) were important parameters for characterization of fractures in engineering materials. The relationship between J-integral and COD has been investigated for a long time and was enerally represented as J = m σyδ, where σy is the yield strength and m is a function of specimen geometry and material properties. To determine the value of m, extensive studies and experiments have been performed. The method that used the fracture-surface topography analysis (FRASTA) for determining J-integral from fracture surfaces of materials was introduced. On the basis of the relationship between COD and fracture surface average profile, the relationship between J-integral and COD was deduced and compared with the generally used equation. The method was experimentally confirmed to be able to provide a new way to determine the relationship between J-integral and COD.
关键词:
FRASTA
,
null
,
null
Zhenya Zhang
材料科学技术（英文）
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
S Narayan
,
A Rajeshkannan
钢铁研究学报(英文版)
An experimental investigation on the workability behaviour of sintered Fe-035C steel preforms under cold upsetting, have been studied in order to understand the influence of aspect ratio and lubrication condition on the workability process. The above mentioned powder metallurgy sintered preform with constant initial theoretical density of 84% of different aspect ratios, namely, 04 and 06 respectively were prepared using a suitable die-set assembly on a 1 MN capacity hydraulic press and sintered for 90 min at 1200 ℃. Each sintered preform was cold upset under nil/no and graphite frictional constraint, respectively. Under the condition of triaxial stress densification state, axial stress, hoop stress, hydrostatic stress, effective stress and formability stress index against axial strain relationship was established and presented in this work. Further more, attained density was considered to establish formability stress index and various stress ratio parameters behaviour.
关键词:
powder metallurgy
,
failure analysis
,
plastic behaviour
,
workability
Transactions of Nonferrous Metals Society of China
The influence of Zr and Y on the cast microstructure of a nickel-based superalloy was investigated by optical microscopy (OM), scanning electron microscopy(SEM), electron probe micro-analysis (EPMA) and X-ray diffraction (XRD). The gamma+gamma' eutectic volume in the superalloy rises notably with the increase of Zr or Y content. Meanwhile, the morphologies of primary MC carbides change from needle and platelet-like to blocky shape with increasing Zr and Y doped. The XRD results show that the primary MC carbide lattice constant increases with Zr and Y additions, and EPMA investigation shows that the platelet-like MC carbides contain primarily Nb and C, while those carbides in blocky shape have 39.2% Zr and 39.6% Nb in average,. These influences on the cast microstructure can be attributed to the atomic size effects of Zr and Y.
关键词:
yttrium;zirconium;carbides;nickel based superalloys;microstructure;solidification;carbide morphology;mechanical-properties;boron;ni3al;yttrium;sulfur
惠雪梅
,
王晓洁
,
尤丽虹
,
王益
,
全小平
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2006.z1.011
通过地面环境模拟实验,分析了高模碳纤维/环氧树脂改性氰酸酯复合材料(M40J/CE/EP)的表面元素,研究了高真空加热环境下复合材料的真空出气性能和出气气体成分.结果表明,M40J/CE/EP复合材料的表面主要由C、O、N元素构成;经高真空加热后,复合材料的出气气体成分以小分子挥发物和碳氢化合物电离碎片为主,有可能在空间低温条件下冷凝在航天器的敏感器件表面而造成污染;通过真空出气性能实验测得,M40J/CE/EP复合材料的总质量损失(TML)的平均值为0.27%,收集到的可凝挥发物(CVCM)为0,完全达到出气筛选合格的指标要求.
关键词:
氰酸酯树脂
,
复合材料
,
出气
,
X射线光电子能谱
