MA Zheng-huan
,
ZHAO Xiang-juan
,
GE Chang-sheng
,
DING Tie-suo
,
LI Jun
,
XIAO Xue-shan
钢铁研究学报(英文版)
A new family of resource-saving, high chromium and manganese super duplex stainless steels (DSSs), with a composition in mass percent, % of Cr 0.29, Mn 0.12, Ni 2.0, Mo 1.0, and N 0.51-0.68, has been developed by examining the effect of N on the microstructure, mechanical properties and corrosion properties. The results show that these alloys have a balanced ferrite-austenite relation. The austenite volume fraction decreases with the solution treatment temperature, but it increases with an increase in N content. The increases in nitrogen enhance the ultimate tensile strength (UTS) and reduce the ductility of the material slightly. The pitting corrosion potential increases first and then decreases with an increase in nitrogen content when the amount of N arrives to 0.68%. The yield stress and ultimate tensile strength of solution-treated samples were more than 680 and 900 MPa, the elongation of experimental alloys are higher than 30%, respectively, what is more, the pitting potentials were beyond 1100 mV.
关键词:
duplex stainless steel
,
microstructure
,
mechanical property
,
pitting potential
Ximiao PAN
,
Zhanpeng JIN
材料科学技术（英文）
The phase equilibrium relations of the ternary Ni-Cr-Zr system at 900°C have been investigated by means of diffusion triple and electron probe microanalysis (EMPA) techniques. A series of tie lines and triangles have been determined, and the corresponding tentative isothermal section is presented based on the current information.
关键词:
Nickel
,
null
,
null
,
null
Journal of Alloys and Compounds
The subsolidus phase relations in the ZnO-MoO3-B2O3, ZnO-MoO3-WO3 and ZnO-WO3-B2O3 ternary systems have been investigated by the means of X-ray powder diffraction (XRD). There is no ternary compound in all the systems. There are five binary compounds and five tie lines in the ZnO-MoO3-B2O3 system. This system can be divided into six 3-phase regions. There are three binary compounds and three tie lines in the ZnO-MoO3-WO3 system. This system can be divided into four 3-phase regions. There are four binary compounds and four tie lines in the ZnO-WO3-B2O3 system. This system can be divided into five 3-phase regions. The possible component regions for ZnO single crystal flux growth were discussed. The phase diagram of Zn3B2O6-ZnWO4 pseudo-binary system has been constructed, and the result reveals this system is eutectic system. The eutectic temperature is 1007 degrees C and eutectic point component is 70 mol% Zn3B2O6. (c) 2007 Elsevier B.V. All rights reserved.
关键词:
ZnO-MoO3-B2O3;ZnO-MoO3-WO3;ZnO-WO3-B2O3;Zn3B2O6-ZnWO4;phase relation;zno single-crystals;zinc oxide;growth;moo3-wo3
Surface & Coatings Technology
Tensile fracture behavior of thermal barrier coatings (TBCs) on superalloy was investigated in air at room temperature (RT). 650 degrees C and 850 degrees C. The bond coat NiCrAlY was fabricated by either high velocity oxygen fuel (HVOF) or air plasma spraying (APS), and the top coat 7%Y(2)O(3)-ZrO(2) was deposited by APS. Thus two kinds of the TBC system were formed. It was shown that the coating had little effect on tensile stress-strain curves of the substrate and similar tensile strength was obtained in two kinds of the TBC system. However, the cracking behavior in the two kinds of TBC system at RT was different, which was also different from that at 650 degrees C and 850 degrees C by scanning electron microscopy. The interface fracture toughness of the two kinds of TBC system was evaluated by the Suo-Hutchinson model and the stress distribution in the coating and substrate was analyzed by the shear lag model. (C) 2011 Elsevier B.V. All rights reserved.
关键词:
Thermal barrier coating;Air plasma spraying;High velocity oxygen fuel;Tensile fracture;Interface fracture toughness;mechanical-properties;interface;crack;tbcs
Surface & Coatings Technology
In order to reduce the high brittleness of laser clad Fe-B coatings, the composite Fe-Ti-B coating was developed by laser cladding with a powder mixture of B4C and Fe-Ti alloy. The microstructure, hardness and cracking resistance of these coatings were investigated in this paper. The experimental work enables the following findings to be reached: (i) the needle-like TIE, whiskers could be synthesized in situ using the laser cladding method in the composite Fe-Ti-B coating. (ii) The size, shape and volume fractions of TiB2 whiskers in the composite coating are greatly dependent upon powder compositions (contents of B, Ti elements and the ratio of B/Ti elements) and the laser energy density used. The average ratio of width/length for the synthesized TiB2 whiskers increases with increasing laser energy density and ratio of B/Ti elements in this coating. (iii) Both the hardness and cracking resistance of the Fe-B laser clad coating could be improved by the formation of TIE, whiskers. (C) 2001 Elsevier Science B.V. All rights reserved.
关键词:
TiB2;laser cladding;coating;steel;microstructure;powders
杨文虎
,
易冉
,
徐阳
,
惠思思
,
曹晓珑
绝缘材料
doi:10.3969/j.issn.1009-9239.2012.01.014
研究了不同外施工频电压下环氧树脂绝缘中的电树枝结构、生长的特性,并用Ding等提出的模型解释了电树枝的发展过程,模拟了其生长曲线.结果表明:在同一电压下,环氧树脂中电树枝的生长速度基本为恒定值,随外施电压的升高,电树枝分枝变少,生长速度基本呈指数增加,且利用模型模拟的生长曲线与实验测试的结果吻合,最后讨论了模型的物理基础.
关键词:
电树枝
,
环氧树脂
,
劣化
,
动力学
,
模型
,
模拟
Haihua LIU
金属学报(英文版)
doi:10.1016/S1006-7191(08)60120-9
A novel method was reported to measure the remnant magnetic field in Lorentz mode in a FEI Tecnai F20 transmission electron microscope equipped with a Lorentz lens. The movement of the circle Bloch line of the cross-tie wall in Permalloy is used to measure the remnant magnetic field by tilting the specimen and adjusting the objective lens current. The remnant magnetic field is estimated to be about 17 Oe, in a direction opposite to that of the objective lens magnetic field. The remnant magnetic field can be compensated by adjusting the value of the objective lens current.
关键词:
Lorentz electron microscopy
,
Lorentz lens
,
remnant magnetic field
,
Permalloy
,
cross-tie walls
陈伟亮
,
张宁
,
唐昭辉
,
丁学勇
材料研究学报
将Miedema模型与实验数据相结合得到适于Miedema模型的O和S的参数(O:电负性7.04、电子密度6.03、摩尔体积4.59;S:电负性5.8、电子密度3.24、摩尔体积6.97),计算了141种O的二元化合物和145种S的二元化合物生成焓其平均绝对误差(MAPE)分别为36.8％、32.4％.结合Ding导出的三元系相互作用系数计算模型,计算了1873 K时Fe基熔体中O和S与其它元素之间的相互作用系数.与实验数据的比较表明,除个别元素外,计算值与实验值之间误差不大且变化趋势比较一致.将误差较大的Nb、Ag、Pt的电负性参数由原来的4.05、4.35、5.65修正为4.31、4.17、5.57,使用Miedema模型的计算精度有很大的提高.
关键词:
材料科学基础学科
,
Miedema模型
,
含O和S熔体与合金
,
相互作用系数
,
参数的修正
汤清虎
,
赵培真
,
张庆红
,
王野
催化学报
分别采用模板剂离子交换法(TIE法)、水热合成法(DHT法)及浸渍法合成了Co-MCM-41,此催化剂能够在无共还原剂存在条件下催化以氧气为氧化剂的烯烃环氧化反应. 另外考察了催化剂的结构特别是钴的存在状态与催化性能之间的关系,以期能够弄清催化环氧化反应中催化剂活性位的本质. X射线衍射及N2吸附-脱附等结果证实,当导入分子筛中的钴的量在2.2%以下时,所有的Co-MCM-41均具有规整排列的六方孔道结构. 漫反射光谱和H2程序升温还原等结果表明,通过TIE法合成的样品中钴主要以孤立态钴离子(single-site Co(Ⅱ))形式存在,而以DHT法合成的样品中钴主要以微晶态Co2SiO4形式存在,浸渍法合成的样品中则存在大量颗粒状氧化钴. 催化反应结果表明,当钴含量均接近1.0%时,采用 TIE法合成的样品的苯乙烯转化率为45%,而用DHT法和浸渍法合成的样品的苯乙烯转化率均低于30%. 考虑到氧化钴和Co2SiO4的低活性以及DHT法和浸渍法合成样品中可能存在一小部分孤立态钴离子,我们推测MCM-41中的孤立态钴离子是催化活化分子氧发生环氧化反应的高效活性位.
关键词:
钴
,
MCM-41分子筛
,
孤立态钴
,
硅酸钴离子
,
氧化钴
,
苯乙烯
,
氧气
,
环氧化
