高速电喷镀制备纳米PTFE镍基复合镀层

研究了以Q235和65Mn钢为基底,经高速电喷镀形成的纳米PTFE镍基复合镀层,考察了喷射速度对镀层沉积速率、表面显微硬度、结晶组织形貌以及镀层结合力的影响,探讨了喷射速度影响镀层性能组织的原因机理。结果表明,喷射速度在4.2～6.3m/s时获得的镀层有较高的沉积速率和表面硬度,晶粒细小、组织致密,镀层结合力较高。     

Al-5%Fe合金的热速处理研究

研究热速处理工艺对Al-5?合金力学性能和初生Al3Fe相形貌的影响.研究结果发现,未热速处理时,初生Al3Fe相为粗大的针片状或针状;初生Al3Fe相占基体的面积百分率为40.39%;合金的抗拉强度为107 MPa.经热速处理后,小部分初生Al3Fe相长成细小的针状,大部分则长成针点状;初生Al3Fe相占基体的面积百分率达到50.77%;抗拉强度达到145 MPa,提高35.5%.研究认为,热速处理之所以能细化初生Al3Fe相是由于高温过热减小了Al与Fe之间的原子团簇,最大限度地消除了合金的遗传性和增大了形核过冷度.     

HA/Ti composite for biomedical application by mechanical milling

In order to overcome the poor mechanical properties of HA and the low bioactivity of Ti,HA/Ti composites with various compositions were prepared by mechanical milling.The effects of milling condition and the composition on the microstructure,the density and the hardness of the composites were studied.The results show that during the ball milling process.Ti particles are refined and the homogeneity of the HA/Ti mixtures is improved;HA will partially decompose due to the existence of Ti and high sintering temperature.The microstructure of HA/Ti composites is highly dependent on the milling condition and the composition.In the microstructure.Ti phase connects to be a continuous network,and HA/Ti mixtures disperse in the network.The longer the milling time,the finer the network will be.The density of HA/T composites decreases with the content of HA increasing and the milling time prolonging,because HA deteriorates the sinterability of Ti.The hardness of HA/Ti composites increases firstly with the content of HA increasing,and then drops when the content of HA exceeds 30%.Addition of HA will strengthen the HA/T composite but will decrease the density of the composite,which accounts for the effect of HA on the hardness of the composites.     

球形旋转接头胀形加工的模拟研究

利用MARC软件,采用特定加载路径分别对球形旋转管接头外管及内管的胀形过程进行了二维数值模拟,分析了所选两种加载路径对胀形时管材形状及壁厚分布的影响,进行了球形旋转管接头液压胀形试验,成功试制出合格旋转管接头,为管接头的胀形加工提供了理论依据。     

全球铝轧制工业概览系列综述之九——日本神户钢铁公司真冈铝板带轧制厂

对日本神户钢铁公司枥木县真冈轧制厂的方方面面作了较全面的介绍，并对神户钢铁公司与美国铝业公司的合资企业－－神钢－美铝铝业有限公司作了附带的描述。这两家企业都是从上世纪70年代以来新建的高起点、高水平、高标准、高质量的世界级的铝板带轧制厂，前者的建设时间历20余年，是一步一步壮大的，原来（1＋3）式热连轧生产线，后改为（1＋4）式的，还有进一步改为（1＋5）式的余地。这是一个综合性强的铝板带加工厂，除生产罐料处，还可生产各种热处理可强化的硬合金板带材。该厂可作为中国今后建设全新的大型现代化铝板带轧制工程的模式。     

SPHC钢在不同冷却条件下的相变规律研究

采用Gleeble1500热模拟试验机及DT-1000膨胀仪测定SPHC钢的连续冷却转变曲线,观察了不同变形及冷却工艺条件下的金相组织。结果表明,SPHC钢的金相组织由铁素体和少量珠光体组成,随着冷却速度的增加,其晶粒细化,强度提高。变形条件下的相变开始温度和终了温度大于未变形条件下的,并且其晶粒直径比未变形条件下的小1μm左右。     

矩形坯连铸生产CrMo系列汽车用钢

简述汽车用钢的发展,对首钢采用BOF-LF精炼-矩形坯连铸-优质棒材轧制工艺路线生产CrMo系列汽车用钢的情况进行总结,认为工艺设计合理顺行.     

空气-乙炔碳氮氧离子多元共渗工艺研究

用空气-乙炔混合气体作为气源,对40Cr钢进行了离子碳氮氧多元共渗;用光学金相显微镜、X射线衍射仪和显微硬度计,对渗层形貌、物相和显微硬度进行了分析检测。结果表明:乙炔浓度是影响性能的关键因素,它对硬度、物相起着决定性的作用。与常规离子渗氮相比,以空气-乙炔混合气体作为气源的碳氮氧离子多元共渗工艺操作简便,成本低廉。     

Research of quasi-solid fracture behavior of casting Al-4.5Cu alloys

The influencing mechanisms of elements Ti and Ce and their interactions on fracture behaviors of casting alloys Al-4.5Cu-0.6Mn were studied by observing tensile fracture behavior in quasi-solid zone under SEM and EDX instruments.The results indicate that the resistance stress against hot cracking can be improved obviously by addition of Ti, because of its grain refining function. It is also found that, when Ce is added into the alloys, besides its effect in refining crystalline, the mechanical behavior of lower melting point eutectic phase in quasi-solid zone can be improved efficiently by some compounds with Ce formed and deposited between dendrites. Therefore, a coiligating effect of Ti and Ce on improving resistance stress against hot cracking is more efficient than that only single alloy element is applied. When hot cracking occurs, grains yield at first, and then crack spreads. Both inter-grain and trans-grain fractures are observed, but the major fracture manner is brittleness.     

Ti3SiC2在900℃与1000℃下的热腐蚀行为

研究了Ti3SiC2三元层状陶瓷材料在900和1000℃下由Na2SO4盐膜引起的热腐蚀行为，用XRD及SEM分析了腐蚀产物膜的成分、结构和形貌等。实验表明，腐蚀膜由TiO2和SiO2混合组成：在结构上明显地分成两层，外层晶粒粗大且多孔，内层晶粒细小且致密。Ti3SiC2与熔融盐接触时遭受较严重的腐蚀。