铸铁件电弧冷焊熔合区白口组织的控制

进行了冷焊条件下控制铸铁件焊补区白口组织的试验．结果表明，采用Ｓｉ－Ｃａ－Ａｌ－Ｂｉ系合金粉层对焊补熔合区进行集中强石墨化孕育处理及焊前在缺陷表面形成Ｎｉ基合金粉末喷涂层，均可消除熔合区白口     

K4169铸件凝固温度场及晶粒组织计算机模拟

研究了在PRO/E和ANSYS软件环境下对复杂铸造系统进行联合建模的方法,采用PRO/E构建K4169高温合金壳体铸件,导入ANSYS软件构建铸造系统并对其凝固过程中的温度场进行模拟,得到铸件各点温度随时间的变化规律及其温度场的分布特征。根据铸件中各特征点的冷却曲线,采用非连续形核模型获得晶粒组织特征值,基于元胞自动机的方法实现镍基高温合金铸件关键部位凝固组织演变过程的可视化仿真。模拟结果与实测晶粒组织符合较好。     

定位板冲孔-整孔-落料级进模设计

对定位板零件的冲压工艺进行了分析,改用冲孔-整孔-落料连续冲压工艺,可明显提高工件质量及生产率.简述了定位板冲模的排样图、冲压力及压力中心等工艺计算,设计了冲孔-整孔-落料级进模.     

具有梯度结构的涂层硬质合金刀片

研究了Co和Ti(CN)含量对梯度硬质合金的力学性能、梯度结构的影响.测试了梯度硬质合金刀片的切削性能.结果表明:随着合金钴含量的增多,合金梯度层厚度增厚,梯度结构越明显;合金的强度提高,磁饱和提高,磁力、硬度和密度减小.随着合金Ti(CN)含量的增多,合金梯度层厚度有变薄的趋势;随合金的硬度提高,合金的强度和密度减小.切削试验表明:具有梯度结构涂层硬质合金刀片的切削性能比无梯度结构涂层硬质合金刀片的切削性能优良.达到同一磨损高度hB=0.15 mm时,前者的切削寿命较后者提高了近一倍.同时随着合金钴含量的增多,硬质合金刀片的切削性能提高.     

Influence of diurnal and seasonal temperature variations on the detection of corrosion in reinforced concrete by acoustic emission

Chloride rich reinforced concrete prisms were coupled to chloride-free prisms and exposed to diurnal and seasonal temperature cycles typical of those found in the UK. Acoustic emissions (AE) and galvanic currents were continuously monitored and correlated with ambient temperature. AE and galvanic currents were found to emulate the evolution of temperature in the diurnal cycles, although no specific relationship between AE and galvanic current could be obtained. The influence of seasonal variations in galvanic current had no obvious influence on AE Energy per second over the range of corrosion rates studied. The findings suggest that AE is more sensitive to short term (diurnal) changes in corrosion rates than the longer (seasonal) effects. It was hypothesised that this is due to transitory changes in the internal microclimate of the concrete.     

Al-Cu合金时效初期的价电子结构

用固体经验电子理论(EET)对Al-Cu合金时效初期的析出相的价电子结构进行计算.计算结果表明:合金基体析出的共格GP区、θ″相,具有比基体更强的共价键络,提升了合金的整体键络强度.从价电子结构层次上解释了时效初期的GP区和θ″相对合金强化作用的内在原因.     

关于现阶段我国高等教育机会均等的思考

高等教育机会均等是在才能(高考成绩)基础上城乡居民对高等教育需要的满足程度基本相同。文章考察了计划经济体制和市场经济体制条件下我国高等教育机会均等的现状,认为造成这种机会不均的根本原因是我国城乡二元结构,体现均等的有效策略只能是城乡基础教育协调发展。     

端盖板高速连续级进模设计

根据制件的形状和生产要求，对RF-300C系列微电机端盖板的结构及工艺性进行了分析。介绍了一副轴承室深度和内径可调的端盖板高速连续级进模的排样设计和模具结构，分析了它的结构以及主要零部件的设计特点；叙述了压凸包、整形、打麻点、落料复位等模具结构在高速连续级进模中的设计方法。实践证明该模具结构可靠，运行状态稳定，制件质量符合技术要求。     

Effect of electric pulse treatment on solidification structure of an A1-15%Si alloy

The effect of electric pulse modifying on the solidification structure of an Al-15%Si alloy was investigated. The result shows that the primary silicon disappears sometimes and the eutectic phase is refined after the treatrnent of EP （electric pulse） though there are different modalities in different treating durations. DSC （differential scanning calorimetry） analysis indicates that the super-cooling texture decreases and the freezing range narrows evidently after the electric pulse treatment.     

晶界对低压电解电容器铝箔腐蚀结构的影响

采用扫描电子显微镜和背散射电子取向成像技术分析研究了低压电解电容器用阳极铝箔的腐蚀结构、晶粒尺寸和晶界分布对比电容的影响及相关机理.结果表明,在铝箔的晶界附近,尤其是大角度晶界附近容易出现尺寸较大的腐蚀孔坑或沟道,造成腐蚀结构的不均匀性并降低比电容.该晶界优先腐蚀的现象起因于晶界的高缺陷密度和与之相应的腐蚀电流密度的局部集中.增加晶界密度可以降低杂质原子偏聚程度和电流密度分布的不均匀性,因此在一些特定的电化学腐蚀条件下可以借助减小晶粒尺寸的方式提高比电容.