高频震实台在消失模铸造生产线上的应用

介绍消失模铸造工艺对震实台的要求,高性能的震实台在消失模铸造中的重要性,并介绍美国GK公司的HDCT型重型高频震实台基本组成、性能特点以及在消失模铸造生产线的应用情况.     

有色合金用呋喃树脂砂溃散性的研究

呋喃树脂砂用于有色合金铸造时，由于浇注温度低，型芯的演散性较差。对于薄壁铝合金铸件和厚大型芯该问题尤其明显。为解决这个问题，作者以ＫＪＮ－Ⅲ型呋喃树脂自硬砂为对象，就其在不同加热温度下的温度场、残留强度及热强度进行了系统的研究。通过对树脂添加剂与残留强度之间关系的研究，得到几种较好的树脂添加剂。在合适的加入量下，可使呋喃树脂砂的残留强度下降４０％～８０％，取得了令人满意的结果。     

唐钢薄板坯连铸连轧生产线质量控制系统分析

简要介绍了唐钢薄板坯连铸连轧生产线的工艺流程和产品大纲，重点对连铸和轧钢过程中的质量控制系统进行了说明和分析。由于生产线采用了第3代薄板坯连铸连轧技术，其产品规格可以“热”代“冷”，可满足用户对产品高品质的要求。     

采用模式搜索法对磁悬浮列车轨道梁的加工实现精确定位

磁悬浮列车轨道梁体积大、质量重,无法适用传统机加工定位方式,需由机床进行测量并与理论模型进行拟合以确定其加工位置。针对定位过程中的拟合问题,文章基于最小二乘原理,采用模式搜索法对理论模型和实际模型进行拟合,使其满足每个实测点与其对应理论点的距离的平方和为最小,从而实现对加工位置的精确定位,并得到从理论模型到加工模型的坐标变换参数和转换矩阵。     

Performance of positive and negative electrodes in amorphous manganese oxide supercapacitor

Using potassium permanganate and acetic manganese as the reactants, amorphous manganese oxide was prepared with mechanochemical method. XRD was used for microstructure characterization, while cyclic voltammetry and constant current charge-discharge were used for electrochemical performance testing. The positive electrode （PE） and negative electrode （NE） were investigated respectively in amorphous manganese oxide supercapacitor, aiming to find their different performances in charging-discharging. The results show that the crystalline structure is destroyed in both the PE and NE material during charge-discharge process. Thereinto, the NE suffers a bit more seriously. When cycling, the PE potential scope diminishes while the NE potential scope enlarges. The increased inner resistance makes the NE curves almost bended to be a right angle, but not the PE curves. The cell＇s equivalent series resistance （ESR） is more dependent on the NE, and the capacitance is mainly determined by the rapid descent of the NE potential range. The capacitances of the NE are highly rate-dependent, decreasing from 121.3 to 53.1 F/g, by 56.2%, over the range of 5-25 mV/s. However, the PE appears to be weakly dependent and its capacitance is only dropped by 22.1%.     

Effect of ball milling process on the microstructure of titanium-nanohydroxyapatite composite powder

Titaninm-nanohydroxyapatite （Ti-nHA） composite powders, composed of titanium with 10 vol.% and 20 vol.% of nano-hydroxyapatite, were milled in a planetary ball mill using alcohol media to avoid excessive heat. XRD and SEM were performed for characterization of the microstructure, and the homogeneity of Ti/HA nanocomposite powder was evaluated by EPMA with prolonged ball milling time. The results show that under the condition of wet milling, the grain size of Ti-nHA composite powders is decreased with the increase in ball milling time and the amount of the addition of nHA. While for milling of 30 h, the nanocomposite powder with free structure, which consists of the nano-hydroxyapatite （nHA） particles and titanium （Ti） phase, is obtained. Three stages of milling can be observed from the dement mapping of Ti, Ca, and P by EPMA; meanwhile, it is found that the nHA would be more homogenously distributed after milling for 30 h.     

镁合金散热片挤压成型工艺研究

针对AZ31B镁合金的特点,选择不同的挤压温度进行散热片的挤压试验,研究结果显示:AZ31B镁合金在400℃×20 h均匀化退火,挤压温度400℃,挤压速度1.0~2.5 m/min的工艺条件下,具有良好的热挤压性能,可获得具有较高的强度、较好的延展性及复杂断面的散热片。     

铸件热节变化与冒口位置的分析

热节是铸件凝固慢的节点或区域,可分为几何热节、物理热节、接触热节和流动热节.热节的位置、大小受铸件结构、铸型材质和浇冒口系统的开设位置所影响.冒口的开设应使接触热节、流动热节与几何热节分离.     

Sm—Fe—N永磁体的研制

用机械合金化的方法及退火和渗氮处理,用纯Fe粉和Sm粉制备出内禀矫顽力为33.1kA/cm(41.6kOe)和磁能积为98.7kJ/m~3(12.4MGOe)的Sm—Fe—N永磁材料.用X射线衍射方法对样品制备过程中的机械合金化、晶化、渗氮过程中所形成的相进行了分析,用脉冲磁强计测量磁性实验结果发现,采用高能球磨机是机械合金化的方法制备高矫顽力永磁体的较好工具晶粒尺度为几十nm是获得高矫顽力Sm—Fe—N永磁体的重要因素,样品中存在的软磁第二相是磁滞回线中出现蜂腰形状的主要原因。     

硅酸铝短纤维铝基复合材料耐磨性研究

本文研究了以硅酸铝短纤维作增强体，工业纯铝L00，铸造铝合金ZL101为基体的复合材料耐磨性。并与以颗粒状Al_2O_3为增强体进行对比。结果表明：硅酸铝纤维／ZL101复合材料的耐磨性为ZL101的321倍。在相同摩擦条件下，基体相同的铝基复合材料，以硅酸铝短纤维作增强体较以颗粒Al_2O_3为增强体有着更高的耐磨性。应用摩擦理论推导了磨损方程■与实测吻合。