稀土对10SiMnNb钢显微组织的影响

冶炼低硫钢10SiMnNb 和10SiMnNbRE 钢。测定了10SiMnNbRE 钢中固溶0.035wt%RE。研究了稀土元素对先共析铁素体析出,珠光体转变,贝氏体转变和马氏体转变的影响。结果表明,固溶稀土增加了过冷奥氏体的稳定性,在相同的冷却速度下,添加稀土元素和无稀土元素比较,显微组织显然不同,先共析铁素体量减少,珠光体量增加,粒状贝氏体量增加,并细化了马氏体组织。     

微合金化稀土对结构钢相变及组织的影响

本文论述了稀土固溶的概念及稀土在钢中的存在形式。研究了稀土对几种低碳、中碳、高碳结构钢的临界点、CCT曲线和显微组织的影响。试验表明,稀土使钢的A_(cl)、A_(r1)、A_(c3)、A_(r3)、M_(s)、M_f、B_s点温度有所降低;稀土不改变CCT曲线的形状,但使其向右下方移动;在相同的冷却速度下,添加稀土元素和无稀土元素的钢比较,先共析铁素体量减少,珠光体量增加,并细化了珠光体及马氏体组织。     

压缩变形对BNbRE钢组织的影响

利用Gleeble-1500热模拟试验机研究了变形量、变形道次数等对BNbRE钢组织形态的影响.利用光学显微镜和扫描电子显微镜,观察了BNbRE钢试样的组织形态,利用洛氏硬度计测试了试样的硬度值.结果表明,随着变形量的增加,BNbRE钢显微组织明显变细.变形量越大,珠光体的片间距就越小,珠光体的强度和硬度就越高.在其他条件相同时,变形道次数对BNbRE钢显微组织影响不大.     

BNbRE钢中的稀土

冶炼了不同稀土含量的BNbRE钢,用内耗法测定了稀土在钢中的固溶情况,用扫描电镜分析了钢中的夹杂物,测定了不同稀土含量钢的连续冷却曲线,确定珠光体转变温度.结果表明,BNbRE钢中的稀土可以在钢中固溶,剩余稀土与夹杂物发生作用,形成稀土复合夹杂物,改变了夹杂物形态、尺寸;稀土降低了珠光体转变温度.     

稀土-镁球铁正火态组织的耐磨性研究

本文对影响稀土-镁球铁正火态组织的耐磨性因素进行研究。研究结果表明:正火态组织耐磨性取决于珠光体量和珠光体加工硬化率的大小,后者是提高耐磨性的主要方面。     

稀土对BNbRE重轨钢组织及临界点的影响

研究了BNbRE钢中残留稀土元素对其相变临界点、退火后珠光体组织及热轧态奥氏体晶粒的影响.结果表明,钢中残留稀土元素使Ar1温度降低,Ms温度升高;奥氏体晶粒细化,铁素体量减少,珠光体量增多.     

稀土对BNbRE钢夹杂物的影响

研究了稀土对BNbRE钢组织的影响，结果表明，稀土改变了钢中夹杂物的形态和尺寸．     

稀土氮碳硼共渗对45钢组织及性能的影响

通过对45钢不加稀土与加稀土碳硼共渗层组织及相结构的分析,说明稀土对共渗层组织及性能的影响。试验结果表明,当渗剂中稀土加入量一定时,可显著提高45钢表面的耐磨、而蚀和抗疲劳性能。     

形变对65Mn钢中氢扩散的影响

用电化学渗透法研究了拉伸形变对６５Ｍｎ钢三种组织珠光体、球化珠光体、回火索氏体的氢扩散系数和陷阱参数的影响．结果表明，扩散系数在开始形变时有一陡降，然后基本上随形变量呈直线下降，并在一定形变量（５～６％）后基本上保持不变．测得预充氢和不预充氢形变的陷阱能分别为５８～６４ＫＪ／ｍｏｌ和３０～３８ＫＪ／ｍｏｌ．     

3Cr2W8钢的珠光体转变

制定了测定珠光体转变的实验工艺，进行了热处理工艺实验．结果表明，在实验条件下3Cr2W8钢得到了粒状珠光体．研究了珠光体形核、核长大的过程，做出了珠光体转变动力学曲线以及随珠光体转变量的不同，3Cr2W8钢硬度的变化曲线．     

碳、硅含量对重载车轮钢显微组织的影响

利用金相显微术、扫描电镜、透射电镜以及X射线衍射测量技术研究碳、硅含量对重载车轮钢显微组织的影响。结果表明:重载车轮钢的显微组织由珠光体和少量先共析铁素体组成,适当降低碳含量、增加硅含量不仅使珠光体含量减少,而且导致珠光体的片层间距增大;与珠光体团内层片状组织相比,珠光体团界处的渗碳体不再呈片状、而是以颗粒状不连续分布,同时渗碳体含量相对较少。     

高碳铬钢中等温转变下的碳化物析出

本文用薄晶体透射电镜法，研究高碳铬钢和高碳铬－锰－硅钢等温转变组织的特点。发现，试样中除大量生成珠光体外，还存在两种不同形态的相界面析出一相间沉淀和纤维状碳化物。它们与同时存在的珠光体密切相关。对高、低碳铬钢中相界面析出进行了对比；讨论了高碳合金钢中相界面析出形成的条件；提出了高碳合金钢中相界面析出形成的机理。     

关于钢的珠光体分解

一般认为，珠光体转变得到铁素体和渗碳体的机械混合物，而且存在领先相．应用系统科学的理论和方法，研究了钢中珠光体共析分解机制，否定了领先相的存在．认为，过冷奥氏体的珠光体转变以及所谓“相同沉淀”都是铁素体和碳化物两相的共析共生的分解过程，设计了新的转变模型．实验表明，珠光体分解在奥氏体晶界形核，铁素体和渗碳体具有位向关系．明确指出，钢中的珠光体和“相间沉淀”产物都是共析铁素体和共析碳化物构成的整合组织．     

稀土镁复合处理对X70管线钢组织和性能的影响

采用金相观察、硬度测试、力学性能测试等方法,研究了稀土镁处理对X70管线钢组织与性能的影响.结果表明,微量稀土镁可显著减小晶粒尺寸,提高X70管线钢室温和高温的力学性能;但随温度升高稀土镁对材料的高温力学性能影响会逐步减小.     

Incubation and development of corrosion in microstructures of low alloy steels under a thin liquid film of NaCl aqueous solution

Electrochemical measurement,optical microscopy,and scanning electron microscopy were employed to investigate the corrosion behavior of some low alloy steels.The steels were held under a thin liquid film of 0.5wt% NaCl aqueous solution.It is found that the steels with the same chemical composition but different microstructures exhibit obviously different corrosion behaviors.However,the corrosum behavior of the steels with different compositions but the same microstructures may be suuilar in the present investigation.The corrosion rate of bainite is slower than that of ferrite and pearlite.The corrosion products of bainite are uniform and fine.The size of carbon-rich phases produces a great impact on the corrosion of the steels,whether in the initial stage or in the long term It is easy to induce large pitting for carbon-rich phases with large size,which damages the compactness of the rust layer.     

Deformation bands in fully pearlitic steel during wire drawing

The deformation of fully pearlitic steels during wire drawing has been investigated for both longitudinal section and transverse section by back-scattered electron imaging(BSEI),electron back-scattered diffraction(EBSD),and transmission electron microscope(TEM).The results show that a large number of deformation bands(DBs)composed of a mixture of kink-like bands and shear-like bands were observed both in the longitudinal section and the traverse section of the drawn wires.The formation of such bands involves two aspects:heterogeneous deformation in the scale of pearlite colonies and instability of ferrite-cementite interfaces due to stress concentration during wire drawing.The development of such bands in fully pearlitic steels dominates the formation of metallographic texture,reduces the pearlite interlamellar spacing and promotes the development of<110>fiber crystalline texture of ferrite matrix during wire drawing.     

压力容器用钢氢蚀后组织与力学性能研究

研究了氢腐蚀后２０Ｇ和１５ＣｒＭｏ钢力学性能与显微组织的变化；并用扫描电镜分析了拉伸断口的特征．结果表明：２０Ｇ钢力学性能的下降是由于氢蚀造成珠光体的减少和裂纹的出现；并使断裂机制发生了韧性向脆性的转变．１５ＣｒＭｏ钢具有较强的抗氢腐蚀能力，力学性能的变化是因为严重的表面脱碳造成。抗拉强度的变化对整个氢蚀过程都敏感；而延伸率的变化仅在氢蚀前期敏感。     

Effect of RE on the ignition-proof, microstructure and properties of AZ91D magnesium alloy

The magnesium alloy is prone to burn during die-casting, which limits its applications severely, so the effect of adding rare earth （RE） on the ignition-proof of AZ91D Mg alloy is studied. The results indicate that the addition of mischmetal RE elements has a remarkable influence on the ignition-proof property of the magnesium alloy. It is found that the ignition temperature of the magnesium alloy can be greatly raised by adding a proper amount of RE. When the amount is 0.1wt%, the ignition temperature reaches 877℃ which is 206℃ higher than that of AZ91D without RE and the mechanical properties of the alloy are also improved, However, the amount of RE must be properly controlled because too much RE would induce grain coarsening and reduce the mechanical properties.