高铬铸铁中的碳化物研究

本文介绍了在铸态、预处理工艺以及预处理淬火工艺中锰钼高铬铸铁的组织和碳化物的形态；就预处理淬火工艺下二次碳化物的结构和成分进行了透射电镜分析；结果表明：预处理淬火工艺下，存在铬的M7C3型二次碳化物并呈弥散分布；对高铬铸铁的耐磨性产生积极的影响。     

铁杂质在Eu2+, Dy3+激活的铝酸锶发光粉中发光猝灭研究

利用纳米包覆技术制备了掺杂不同含铁量的发光粉SrAl2O4: Eu, Dy,通过X射线衍射、发射光谱和余辉曲线等测试手段研究了铁杂质对发光粉的晶体结构以及发光性能的影响. 结果表明微量铁的存在没有引起发光粉的晶相结构变化,但降低了发光强度. 随着铁含量从0.001 mol增加到0.01 mol,余辉平均发光强度下降了50%,这种变化是由于Fe3 -O2-中心将一部分能量传递到红外区域引起的,同时首次发现了铁在铝酸锶晶体中的红外发光现象.     

"零保温"淬火温度对27SiMn钢组织和性能的影响

研究了"零保温"淬火温度对27SiMn钢组织和力学性能的影响.探讨了"零保温"淬火条件下,奥氏体成分的不均匀性和马氏体转变的特点.实验表明,"零保温"淬火条件下,830～930 ℃范围内,随淬火温度升高,27SiMn钢的强、硬度和延伸率均增加;高于930 ℃后,逐步下降.该钢"零保温"淬火后得到细小的板条状马氏体组织,其原因与奥氏体晶粒细化和奥氏体中碳元素分布不均匀有关.27SiMn钢缸体采用(900±10)℃淬火,(630±10)℃回火的"零保温"调质处理工艺,力学性能完全满足技术要求.     

LiMn2-2xCoxCrxO3.95F0.05正极材料的合成表征及表面包覆

采用溶胶-凝胶法合成了锂锰尖晶石正极材料LiMn2-2xCoxCrxO3.95F0.05(x=0.05、0.1),并用沉淀法在其表面包覆2%的TiO2.XRD和ESEM分析表明掺杂样品以及掺杂之后再包覆TiO2的样品依然保持尖晶石结构,样品颗粒大小分布都较均匀.电化学性能测试显示LiMn2O4的首次放电容量为124.4 mA.h/g,50次循环后容量损失43.2%,而多元掺杂样品LiMn1.9Co0.05Cr0.05O3.95F0.05和LiMn1.8Co0.1Cr0.1O3.95F0.05的初始放电容量分别为114.7和103.4 mA.h/g,100次循环后容量损失为9.7%和4.1%.LiMn1.9Co0.05Cr0.05O3.95F0.05包覆2%TiO2和LiMn1.8Co0.1Cr0.1O3.95F0.05包覆2%TiO2样品的初始放电容量为109.3和96.6 mA.h/g,100次循环后容量损失为5.0%和3.5%,经过改性后材料的循环性能得到改善.     

淬火速率和锆含量对7055型铝合金晶间腐蚀的影响

研究淬火速率和锆含量对7055型铝合金晶间腐蚀的影响,并结合金相显微镜和透射电镜对其机理进行分析和讨论。结果表明:淬火速率和锆含量的增加都可提高合金的抗晶间腐蚀能力,当锆含量大于0.1%时,合金晶间腐蚀的淬火敏感性明显减小;微量锆的添加阻碍了再结晶,细化了晶粒;淬火速率的提高减小了晶界无沉淀析出带的宽度,因而提高了合金抗晶间腐蚀能力。     

扩散焊接多层材料淬火过程的有限元分析

采用有限元方法模拟了TC4/V/Cu/Ni/GCr15焊后多层材料淬火过程中的温度及应力场,模拟中考虑了轴承钢中马氏体相变的影响. 模拟结果表明:淬火过程中,中间层是应力最为集中的区域,钢中发生的马氏体相变起到了降低应力的作用;中间Cu层是剪切应力最为集中的区域;最大剪切应力出现在马氏体相变前铜层外表面处,是引起工件失效的主要原因;轴承钢层厚度的减小可以明显降低工件中最大剪切应力,但不能从根本上消除引起工件失效的危险因素.     

相变蓄能材料的包覆与性能测试

本实验用硅酸钠、二氧化硅为主要原料,氟硅酸钠为添加材料的复合浆体材料对相变蓄能材料进行了包覆,制备具有固定外观形状的固-液相变材料。实验采用不同实验配方进行包覆后,选择具有较好表观特征的配方进行力学性能测试,测试结果表明,以硅酸钠10ml,二氧化硅3g为主要原料,氟硅酸钠2g,氧化镁1g,盐酸1ml为添加材料配比的复合浆体材料是良好的包覆材料,包覆后的相变材料的维氏硬度为573(kg/mm2)。     

Titanium carbonitride thick coating prepared by plasma spray synthesis and its tribological properties

TiCN coating, owing to its superior wear-resistance, has been frequently applied in many fields. TiCN thick coating was first prepared by reactive plasma spraying. The phase composition, microstructure and tribological properties of the TiCN coating were investigated in this research. Experimental results show that the microstructure of the TiCN coating was quite dense, and there was also a little amount of titanium oxides within the coating. By XPS analysis, Ti-C and Ti-N bonds were detected in the coating. The TiCN coating exhibited superior wear-resistance. The failure mechanism was attributed to the ad-hesive wear, the grinding of TiCN hard-grain, as well as the coating failure by oxidation. There were more Fe, Cr, O, etc. in the failure zone, suggesting that the corrosion propagated gradually from sur-face to interior.     

Mathematical Model of ComputerHeat Treatment and Its Simulation

Computer simulation on heat treatment is the foundation of intelligent heat treatment. The simulations of temperature field,phase transformation, stress/strain complicate quenching operation were realized by using the model of three dimensional non-linear finite element method and the treatment methods of abruptly changing interface conditions. The simulation results basically fit those measured in experiments. The intelligent sealed multipurpose furnace production line has been developed based on the combination of computer simulation on gaseous carburizing and computer control technology. More than 3000 batches of workpieces have been processed on this production line, and all are up to standard. The application of computer simulation technology can significantly improve the loading ability and reliability of nitriding and carburizing workpieces, reduce heat treatment distortion, and shorten carburizing duration. It is recommended that the reliable product design without redundancy should be performed with the combination of the CAD of mechanical products, the CAE of materials selection and heat treatment, and the dynamic evaluation technology of product reliability.     

渗碳淬火件磨削裂纹的分析及防止措施

本文介绍了渗碳淬火件磨削裂纹的成因及对裂纹的防止与消除所取得的一些合理工艺方法。