夹杂物对油井管钢氢致开裂腐蚀的影响

对油井管钢进行了pH 2.0溶液浸泡的氢致开裂(HIC)试验。考察了油井管钢的抗HIC性能,分析了不同种类夹杂物对钢板HIC性能的影响。结果表明,在强酸性腐蚀环境中,夹杂物越多,钢对HIC越敏感。诱发油井管钢氢致开裂的夹杂物主要为MnS夹杂物、Al2O3夹杂物和硅铝酸盐复合夹杂物,其中长条状MnS夹杂物危害最大。夹杂物诱发裂纹的初期形貌为夹杂周围出现空洞,空洞的扩展成为氢致裂纹。     

Ni基P／M Rene 95合金中非金属夹杂物导致裂纹萌生和扩展的扫描电镜原位观察

通过SEM原位拉伸试验观察了P/M Rene 95合金中的非金属夹杂在拉伸状态下导致裂纹萌生、扩展的微观力学行为,结果表明：在原位拉伸过程中,裂纹首先在试样表面的夹杂物处产生,裂纹主要萌生于夹杂物/合金基体的界面;随着外加应力的增加;裂纹极易沿夹杂物/基体界面扩展,向基体深入;最后,部分夹杂与基体完全分离、脱落,一些夹杂物的材料制备过程中被破碎成若干碎片,增加了裂纹萌生的几率。     

Q345R钢板分层缺陷原因分析

对Q345R钢板分层缺陷原因进行了研究。结果表明：分层缺陷钢板的夹杂物超标,且在钢板厚度方向存在明显的偏析线。分层处有明显的点列状孔洞分布,这是引起裂纹扩展的主要原因。钢板的基体组织为珠光体+铁素体,分层处组织为马氏体+少量贝氏体+少量铁素体。裂纹起源处的夹杂物为MnS和Al2O3且以MnS为主,沿着带状组织和夹层分布。分层处的断口形貌为解理断裂,呈片层状或羽毛状,断口有明显的分层现象。分层处的贝氏体、马氏体组织使材料脆性增加,在与MnS夹杂物的共同作用下,形成应力集中而产生裂纹。     

夹杂物对高强钢焊缝金属组织和冷裂纹影响分析

采用自行研制的高强钢药芯焊丝对Q960钢进行了钨极氩弧焊焊接,在研究焊缝金属的组织和抗拉强度,以及25、0、-20和-60℃焊缝金属冲击功的基础上,分析了夹杂物的尺寸、形状和分布对焊缝金属组织中针状铁素体组织形成的影响,以及对焊缝金属冷裂纹形成和扩展的影响。结果表明:当焊缝金属中夹杂物尺寸在0.4～1.0μm之间时有利于针状铁素体形核,形核夹杂物为核壳结构,其核心为Mn、Ti和Al的氧化物,外壳为Mn的硫化物;焊缝金属中有形核夹杂物和非形核夹杂物两种;冷裂纹从非形核夹杂物处形成并向远处扩展,裂纹扩展中遇到形核夹杂物,其周围针状铁素体可阻碍其扩展,若遇非形核夹杂物则会产生二次裂纹。     

16Cr3NiWMoVNbE齿轮钢的疲劳性能与裂纹萌生

采用真空感应熔炼+真空自耗重熔(VIM+VAR)工艺制备16Cr3NiWMoVNbE齿轮钢。测定了试验钢的疲劳极限和S-N曲线。通过观察断口,分析疲劳萌生类型和影响因素。结果表明:疲劳极限强度达到773 MPa,疲劳裂纹萌生于表面驻留滑移带、表面缺陷、近表面夹杂物和次表面夹杂物。表面驻留滑移带萌生疲劳裂纹占13%,表面缺陷萌生裂纹占33.3%,近表面夹杂物萌生占40%,次表面夹杂物萌生占13%。当疲劳裂纹萌生于内部夹杂物时,疲劳寿命随应力的增大而减小;在一定实际应力作用下,疲劳寿命随夹杂物尺寸的增大而减小。随着实际应力增加,疲劳裂纹萌生的夹杂物临界尺寸减小。     

锆脱氧对船板EH36夹杂物和耐蚀性能的影响

为研究脱氧方式对船板夹杂物形态和耐蚀性能的影响,采用锆脱氧和铝脱氧,对比两种脱氧条件下钢板晶粒尺寸、夹杂物形态和耐腐蚀性能。结果表明,锆脱氧试验钢夹杂物主要为钙铝酸盐夹杂、球形复合氧化物;其中,大颗粒和长条状MnS夹杂物的密度较低,夹杂物弥散细小,可以阻止晶界迁移带来的晶粒长大,有效细化钢板晶粒尺寸。锆脱氧形成的钢中细小氧化物可以作为MnS异质形核核心,降低了钢基体MnS夹杂微区电化学腐蚀敏感性与扩展速度;这种复合氧化物电化学稳定性好,与铝脱氧方式相比,可以有效提升钢板耐蚀性能。     

低碳钢连铸坯质量缺陷分析及改进

使用不同的技术手段对冶金反应引起的非金属夹杂物和连铸坯缺陷进行了分析。结果表明,连铸坯试样中夹杂物分布不均匀,夹杂物的尺寸超过了20μm。一些薄膜状的非金属夹杂物由MnS和CaS组成。薄膜状的非金属夹杂物的形成与金属的脱硫相关。大量的薄膜状的非金属夹杂物主要由MnS夹杂所包起来的镁铝尖晶石组成。这是由于液态金属在脱氧过程中A1和MgO的存在造成的。有必要对于连铸坯在浇注前进行充分的吹氩搅拌。     

镍基粉末高温合金中夹杂物的微观力学行为研究

采用扫描电镜原位拉伸和原位疲劳实验,直接跟踪观察人工植入夹杂(Al2O3)的粉末高温合金(P/MRene95)中夹杂物的微观力学行为(特别是裂纹的萌生、扩展以致断裂的过程）。同时，采用ANSYS有限元分析软件，建立含夹杂物的P／MRene95合金的有限元分析模型，计算在受力状态下夹杂物及其周围基体的应力应变场分布，进而从宏观动力学角度分析夹杂物的微观力学行为。     

夹杂物尺寸对粉末高温合金低周疲劳寿命影响的机制

为了研究夹杂物尺寸对粉末高温合金低周疲劳寿命的影响,将夹杂分别位于试样中心、表面、亚表面并改变其尺寸,研究同一位置下,不同夹杂物尺寸对应力应变分布的影响,结果表明:当夹杂物界面上不含微孔洞时,夹杂物与基体尺寸比例在实验室尺度（1:25）到工程尺度（1:10 000）范围内,夹杂物尺寸对应力应变影响很小;工程实际中,缺陷往往会与基体形成不完好的连接界面,即初始损伤破坏——微孔洞。缺陷对寿命的影响原因:夹杂物尺寸越大,它与基体的界面就越大,出现不完好连接和缺陷的概率就会增加,容易在界面处产生初始损伤破坏;当夹杂物界面上含有微孔洞时,随着夹杂物尺寸变大,界面正应力明显增大,界面切应力微弱减小,基体最大正应力和最大塑性应变均明显增大。     

疲劳载荷下P／M Rene95合金中夹杂物的微观行为研究

采用人工植入Al2O3夹杂的试样，通过SEM下的原位试验，动态跟踪及分析了拉－拉疲劳载荷下P／M Rene95合金中表面或近表面夹杂物的微观行为。结果表明：在所研究的夹杂物的尺度范围内，载荷波形对夹杂物的微观力学行为有很大影响。在三角波加载条件下，虽然夹杂物／基体界面更易萌生裂纹，但表面或近表面夹杂物对试样的断裂影响较小；在正弦波载荷条件下，疲劳裂纹的萌生、扩展及试样的断裂均与表面或近表面夹杂物的基本特性有关。而且，降低正弦波加载时的应力幅值可大大提高夹杂物／基体界面疲劳裂纹的萌生寿命。     

Prospects of the Use of Synergetic Approach to Solution of Problems of the Science of Nanomaterials

A synergetic approach to solution of problems of self-controlled synthesis of nanostructures and creation of self-organizing nanotechnologies is considered in connection with the superproblem of creation of materials with functional properties resembling those of biosystems. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005.     

Kinetics of the oxidation of metals — Influence of self-diffusion of metal

The importance of the self-diffusion of a metal during its oxidation by a gas is treated for the cases of nonstoichiometric oxides having either interstitial cation or cation vacancies. We have established a general relationship for the reaction rate when a mixed diffusion process occurs. From this relationship, we have shown that the pressure dependence can be different, according to whether the rate-determining process is the self-diffusion through the metal or through the product.     

Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991.     

Ab-initio calculation of enthalpies of formation of intermetallic compounds and enthalpies of mixing of solid solutions

A large number of ab-initio calculations of energies of formation of intermetallic compounds have been performed in the last 15 years. The currently used methods are listed. The paper presents a review of the aluminium based compounds which have been studied. Comparisons of calculated and experimental enthalpies of formation are provided for aluminim-3d and-4d transition metal alloys at equiatomic composition. The modelling of the enthalpies of mixing of solid solutions based on a given lattice is described.     

试论洋务派教师聘任的思想

洋务派在洋务学堂的办学活动中,为了解决西学专业学科的教学困难,采用了聘请外籍教师的应急措施.他们以真才实学,合同制管理作为主导思想,并认为这种解决师资的途径只是权宜之计,并非久远.从客观上看,洋务派的教师聘任思想有深刻的历史影响.     

胫骨生物陶瓷复合材料的微结构增韧机理

扫描电镜观察显示胫骨是一种由羟基磷灰石和胶原蛋白组成的自然生物陶瓷复合材料.羟基磷灰石具有层状的微结构并且平行于骨的表面排列.观察也显示这些羟基磷灰石层又是由许多羟基磷灰石片所组成,这些羟基磷灰石片具有长而薄的形状,也以平行的方式整齐排列.基于在胫骨中观察到的羟基磷灰石片的微结构特征,通过微结构模型分析及实验,研究了羟基磷灰石片平行排列微结构的最大拔出能.结果表明,羟基磷灰石片长而薄的形状以及平行排列方式增加了其最大拔出能,进而提高了骨的断裂韧性.     

Mechanism of Nucleation of Precipitates of Carbides of Refractory Metals Under Hot Rolling of Automotive Sheet Steel

Metal Science and Heat Treatment - The problem of formation of properties in microalloyed sheet steels is considered. The cause and the possible mechanism of precipitation of carbides of refractory...