反向凝固法生产H90-钢-H90复合带

研究H90-钢-H90反向凝固复合过程中复合层厚度的变化规律以及复合带的组织和性能，探讨界面结合机理。结果表明：随着浸渍时间的增加，复合层的厚度变化经历了凝固生长、平衡相持和回熔3个阶段，钢带的预热温度越低，获得的最大复合层厚度越厚；H90复合层的组织为等轴晶粒，复合界面处Cu和Fe发生了扩散，而Zn未发生明显扩散，扩散层较薄，约为4μm；复合带的界面结合牢固；不同复合层厚度的复合带，其力学性能略有差异，但均达到GB5213——85所规定的F级深冲钢板的力学性能要求。     

不同磁场作用对AZ31镁合金的凝固组织的影响

镁合金是具有优越性能的金属材料,镁合金的加工是目前国内外正在深入进行研究的新课题.实验发现在镁合金的凝固过程中施加低频或静态磁场都能细化晶粒,但静磁场得到的细化效果要优于低频交流磁场,同时随磁感应强度的增加,静磁场细化晶粒的效果明显提高;在静磁场条件下晶界共晶体组织的厚度明显减小,同时在晶内出现了大量细小块状化合物,这有利于改善镁合金的综合性能.     

Mg-Li-Al合金近液相线制浆及部分重熔

采用近液相线铸造方法制备了Mg—5％Li—3％A1合金的半固态浆料。通过对该合金近液相线铸造与常规铸造组织进行比较，以及在不同静置时间、不同冷却速率下对其铸造组织的影响，较详细地分析了近液相线铸造组织的变化过程。试验结果表明，在Mg—Li合金熔炼中，添加2％Ca可实现阻燃，但效果不如对一般镁合金；与常规铸造相比，近液相线铸造可获得均匀、细小枝晶的组织结构；适当静置或提高冷却速率有利于组织的细化和均匀化；在适当的部分重熔工艺条件下，坯料组织可获得较理想的触变组织。     

电磁脉冲焊接新工艺

电磁脉冲焊接新工艺訾炳涛巴启先崔建忠（辽宁省沈阳市东北大学材料与冶金学院１１０００６）电磁脉冲焊接工艺是本世纪６０年代国外兴起的新型焊接方法。它不同于传统的或一般的焊接工艺，不失为一种良好的焊接方法。鉴于我国在这方面的研究与应用尚属空白，在此作一介绍...     

低频电磁铸造铝合金结晶器材料对磁场的影响

低频电磁场作用下铸造铝合金过程中,优化的结晶器应该在电源频率相同、较低的电流下在铝熔体内部能够获得所需要的磁场强度.结合生产实际情况,设计出工业上实用的低频电磁铸造铝合金结晶器.在结晶器外套材料的不同情况下,对低频电磁铸造铝合金过程的电磁场进行了三维有限元数值模拟.模拟结果表明,当结晶器外套为软磁材料时,铝熔体内部磁场强度得到明显加强.     

A novel electroless silver depositing method for magnesium alloys

Depositing silver on magnesium alloy by both electroless plating and organic coatings was studied. The organic coating was made by immersing samples in organosilicon heat-resisting varnish. In this method the organic coating acts as interlayer between the substrate and silver film. When the reaction starts, silver deposits directly on the interlayer. X-ray diffraction and SEM analysis were used to determine the composition and morphology of the interlayer and silver film. The potentiodynamic polarization curves for corrosion studies of coated magnesium alloys were performed in a corrosive environment of 3.5% NaCl（mass fraction） at neutral pH （6.9）. The results indicate that compared with the substrate, the corrosion resistance of coated magnesium alloys increases greatly. Moreover, the method proposed in this work is environmentally friendly, non-toxic chemicals were used. In addition, it provides a new concept for the corrosion inhibition of magnesium alloys.     

Effect of solid fraction on steel-mushy Cu-graphite pressing bonding

The pressing bonding of steel plate to QTi3.5-3.5graphite slurry was studied. The bonding conditions were 620℃ for preheating temperature of steel plate, 530℃ for preheating temperature of dies, 50 MPa for pressure and 2 min for pressing time. The relationship between the solid fraction of QTi3.5-3.5graphite slurry and the interracial mechanical property of bonding plate was obtained. The results show that when the solid fraction of QTi3.5-3.5graphite slurry is smaller than 45.8%, the interracial shear strength of bonding plate increases with the increasing of solid fraction. When the solid fraction is larger than 45.8%, the interracial shear strength decreases with the increasing of solid fraction. When the solid fraction is 45.8%, the largest interracial shear strength of bonding plate 127 MPa can be got, and the interface is made up of Fe-Cu solid solution.     

电磁调质A356合金的组织研究

采用低频电磁场对水平连续铸造方法制备A356合金锭坯，通过金相显微镜观察，比较了磁场频率和电流大小对亚共晶区内初生廿灿形貌、晶粒大小的影响，通过扫描电镜分析，确定电磁场对Si在铝中晶内含量的影响。结果表明：与普通电磁铸造比较，低频电磁铸造可以细化晶粒，获得细小的α-Al组织和共晶组织。随着磁场频率降低，晶粒细化更加明显。而电流的增加也可以使晶粒细化，从而获得α-Al非枝晶组织和细小均匀的共晶组织。施加低频电磁场，可以提高Si在铝中的晶内含量，使共晶区域和晶界变窄，且Si的分布更加均匀。     

近液相线半连续铸造A356铝合金显微组织

采用近液相线半连续铸造法制备铸造A356铝合金，获得金属半固态加工要求的细小，等轴的“非枝晶”组织，研究了铸造温度、保温时间及冷却速度对该组织的影响规律。结果表明，在液相线附近，降低铸造温度，有利于减小晶粒尺寸；晶粒平均等积圆直径最小可达42．6μm，初始固相体积分数最多可达98．4％，同一温度下，晶粒尺寸随保温时间的延长而粗化；冷却速度快，晶粒尺寸细小；同一铸锭，其中心部位的组织比边缘部位的组织粗大，且分布均匀、等轴特征明显。