材料期刊网

Fe(Ni)-Sn体系金属间化合物纳米粒子中初生相的预测

雷军鹏 , 董星龙 , 赵福国 , 吕波 , 黄昊 , 雷明凯

金属学报

以Miedema半经验模型和比热容随温度有效形成热变化的经验公式为基础, 结合基本热力学关系式对Fe-Sn和Ni-Sn体系的有效形成热及有效形成热随温度的变化进行了计算.采 用电弧放电法制备了Ni-Sn和Fe-Sn纳米粒子. XRD结果表明,在Ni-Sn系中金属间化合物的 初生相为Ni3Sn4,而Fe-Sn系中出现的为FeSn2.计算结果与相应纳米颗粒体系的实验结果吻合较好.

关键词: Fe(Ni)-Sn纳米粒子 , Intermetallic compounds

INFLUENCE OF Al ON DUCTILITY IMPROVEMENT BY B IN Ni_3Al ALLOYS

YANG Wenying LU Fanxiu ZHANG Shouhua University of Science and Technology Beijing , Beijing , China Department of Materials Science and Engineering , University of Science and Technology Beijing , Beijing , 100083 , China

金属学报(英文版)

The “order-disorder” model was adopted to calculate the lattice vacancies related to the com- position change in Ni_3Al alloys.A great deal of vacancies,i.e.,the non-stoichiometric vacan- cies,may exist in the Ni_3Al alloys containing Al over stoichiometry,i.e.25 at.-%.This was confirmed by the positron annihilation technique.Therefore,the influence of Al content on the enhancing behaviour of B towards the ductility of Ni_3Al alloys can be understood by the interaction of non-stoiehiometric vacancies and B atoms.

关键词: Intermetallic compounds , null , null

金属间化合物对Sn3.8Ag0.7Cu焊料合金拉伸性能的影响

祝清省 , 张黎 , 王中光 , 吴世丁 , 尚建库

金属学报

摘 要 利用不同凝固速率和等通道挤压法制备不同组织结构的Sn3.8Ag0.7Cu合金, 使其包含不同形貌大小和分布的Ag3Sn金属间化合物; 拉伸曲线的比较分析和变形后组织的电镜观察表明, 大的针状化合物对合金起着纤维增强的作用, 但自身脆性断裂造成空洞, 降低材料塑性; 微细颗粒状化合物起着弥散强化作用; 分布在小的等轴晶粒晶界上的化合物颗粒能够阻碍晶界的滑动, 起到增强的作用.

关键词: 无铅焊料 , Sn3.8Ag0.7Cu alloy , Intermetallic compounds

Effect of a Trace of Bi and Ni on the Microstructure and Wetting Properties of Sn-Zn-Cu Lead-Free Solder

Haitao MA , Haiping XIE , Lai WANG , null , null

材料科学技术（英）

The microstructure and melting behavior of Sn-9Zn-2Cu (SZC) lead-free solder with 3 wt pct Bi and various amount of Ni additions were studied. The wetting properties and the interfacial reaction of Sn-Zn-Cu with Cu substrate were also examined. The results indicated that the addition of 3 wt pct Bi could decrease the melting point of the solder and Ni would refine the microstructure and the rod-shape Cu5Zn8 phase changed into square-shape (Cu, Ni)5Zn8 phase. The addition of Bi, Ni greatly improved the wettability of SZC solder. In addition, the interfacial phase of the solders/Cu joint was typical planar Cu5Zn8 in SZC-3Bi-1Ni alloy.

关键词: Lead-free solder , null , null , null , null

LaFe_(11.4)Si_(1.6)B_y系列化合物的磁性和磁熵变

李福安 , 松林 , 王高峰 , 谢国秋 , 郑立 , 黄焦宏 , 特古斯

功能材料

LaFe_(11.4)Si_(1.6)By(y=0、0.1、0.2、0.3、0.4和0.5)系列化合物,通过添加少量的B后,可以明显的缩短退火时间.晶格常数随着B含量的增加先减小后增大.该系列化合物的热滞很小,B的添加对其热滞几乎没有影响.在外加磁场变化为0～1.5T时,等温磁熵变的最大值从19.1J/(kg·K)(y=0)逐渐下降到7.1J/(kg·K)(y=0.5).该系列化合物在B含量较低时,处于居里温度(T_c)之上,存在比较明显的场致变磁转变特性.随着B含量增加到0.5时,场致变磁转变特性明显减弱.

关键词: 磁熵变 , 磁热效应 , 金属间化合物 , 变磁转变 , 稀土

材料科学技术（英）

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