含锡C--Mn钢中锡的析出相

利用扫描电镜/能谱仪和透射电镜表征了残余元素Sn在C-Mn钢中的存在形式,同时考察了热处理温度对含Sn析出相类型的影响.结果表明:Fe-5% Sn中Sn以第二相形式在晶界与晶内析出;Fe-1.5% Sn-0.2% S中Sn以第二相形式在直径2~4 μm的球形MnS夹杂物上异质析出.透射电镜分析和热处理实验结果表明:在Fe-5% Sn及Fe-1.5% Sn-0.2% S中MnS夹杂上析出的含Sn第二相结构为四方晶系的FeSn₂相.      

Effect of Substrate Composition on Sn Whisker Growth in Pure Sn Films

Pure Sn films deposited on Cu and Cu alloys are prone to spontaneous whisker formation. One way of preventing whisker formation is to alloy Pb into Sn coatings. However, restriction on the use of Pb demands the development of alternative methods for preventing whisker growth. The present work reports the effect of substrate composition on whisker formation and morphology. Despite employing identical plating conditions, long filament-like whiskers grew only on Sn-plated Cu samples and not on brass. The presence or lack of Sn whiskers has been explained via the thermodynamic stability of various intermetallic compounds at the Sn/substrate interface.     

Ag3Sn Morphology Transitions During Eutectic Growth in Sn–Ag Alloys

Metallurgical and Materials Transactions A - Eutectic Ag3Sn can grow with a variety of morphologies depending on the solidification conditions and plays an important role in the performance of...     

Laboratory extrusion of Nb3Sn

A study of laboratory direct extrusion of HIP processed Nb₃Sn has been undertaken to assess the effect of hydrostatic pressure on the ductile fracture process that is observed in simple compression above 1400 °C. (Remanent porosity and low melting point microconstituents provide fracture centers; and void growth, linkage, and gross fracture can proceed rather rapidly, with pore linkage being obvious at the specimen surface after a 15 pct reduction in simple compression.) A rather porous, 1200 °C HIP processed material (5 pct porosity and 2.4 pct of low melting point phases) has been successfully extruded at 1650 °C in round bar form to a 51 pct area reduction with neither extensive pore linkage nor gross fracture. The results imply that little porosity development occurs in the presence of hydrostatic pressure of about twice the flow stress. Moreover, in the absence of free surface conditions, effective strains of the order of 0.7 will produce no more than about 10 pct porosity development under hydrostatic pressures of about one-half of the flow stress. Gross porosity development is associated with free surface deformation. Powdered graphite proves to be a poor lubricant, with the bulk of the extrusion pressure reflecting sticking friction.     

Sn/Ni液/固扩散偶的界面反应

用Sn／Ni液／固扩散偶研究了Sn液体和Ni基体之间的界面反应和生成相序列。结果表明：Sn／Ni液／固扩散偶在773K退火，其液／固界面上首先生成Ni3Sn4相。而在873K退火15min，首先生成Ni3Sn2-HT（高温）相；再随退火时间延长至60min，在液相和Ni3Sn2-HT的界面上生成Ni3Sn4相；当退火时间再次延长至240min，又在Ni3Sn2—HT相与fee（Ni）的界面上生成Ni3Sn相。采用最大驱动力模型，利用Thermo-Calc软件和已有的Ni-Sn二元数据库对Sn／Ni液／固扩散偶的界面反应过程和生成相序列进行了计算与预测，预测结果和实验结果吻合良好。     

静液挤压在内锡扩散铌三锡多芯线材加工中的应用

静液挤压技术已成功地用于内锡扩散Nb_3Sn多芯超导线材的复合加工。该种超导复合材料由包括难熔金属Ta、Nb及低熔点金属Sn的多元金属组合而成,结构复杂,铌芯数目达19×132及55×588。合理选择工艺参数和挤压复合坯锭的构造,可使挤压温升降到180℃以下,避免挤压棒鼓泡及Sn流失。Nb芯、Sn芯及Ta阻挡层在复合线材断面的分布规整均匀。反应热处理后的Nb_3Sn多芯超导线材具有良好的超导电性能,在4.2K、10T的非铜临界电流密度达到1.5×10~5A/cm~2。