摘要高熵合金，与传统合金不同，它没有固定的主元素，而是用五种或五种以上的元 素以等摩尔比或近等摩尔比进行配制、熔炼成型。因为高熵合金的元素组成是多元化 的，因此熔炼时元素趋向于形成简单的结构，如体心立方或面心立方，同时夹杂着一 些晶间化合物相，这样可以提高弥散强化和固溶强化的概率。因此，很多高熵合金可 以表现出更高的强度、硬度、耐磨性、耐腐蚀性等。78241

本文采用合金化的方法研究了三种高熵合金：Sn-Bi-Ag-In-Sb、Sn-Bi-In-Sb-Ge 和   Sn-Bi-In-Sb-Ga。考察了三种合金元素形成低温高熵合金熔炼过程难易；利用金相

（OM）图和扫描电镜(SEM)像推理、验证合金凝固过程中产生的物相以及元素分布 为；通过差式扫描量热仪（DSC）观察合金在升降温过程的吸放热特性，表征合金熔 点或熔程；再由拉伸试验测试合金拉伸性能、观察其形变与断裂。

结论有（1）Sn-Bi-In-Sb-Ag 高熵合金最终形成了 6 种主要成分组织，分别是 InSb、 InAg3、Ag4Sn、Sn、Ag3Sb 和 Ag3Sn；Sn-Bi-In-Sb-Ge 这种高熵合金主要包含了以下 几种成分：Sn、Ge 和 InSb；其中前两种合金在 XRD 衍射中未检测出 Bi 相，可能原 因在于其它元素固溶于 Bi 相内，使得纯铋变为富铋相，而使得晶格发生畸变，导致 晶格衍射峰位偏离较大。也有可能是因为 Bi 相以某一物相为基体，形成某类含量少 于检测限的金属间化合物，使得 XRD 分析仪测不出其峰值与成分。（2）由三种合金 的组织结构来说，Sn-Bi-In-Sb-Ag 和 Sn-Bi-In-Sb-Ge 合金组织为多相组合形成的合金； Sn-Bi-In-Sb-Ga 合 金则是以某一相为基 体， 其上分布 有 BiIn 相 化合物 。（ 3 ） Sn-Bi-In-Sb-Ag 合金的熔点为 141。7℃，Sn-Bi-In-Sb-Ge 合金的熔点为 142。96℃， Sn-Bi-In-Sb-Ga 合金的熔点为 66。99℃。

毕业论文关键词：高熵合金；低温焊料；显微组织；拉伸性能

Abstract High entropy alloys is different from traditional alloys, it has no fixed main element。 It compounds and melts into shapes with five or more in standard of an equimolar ratio or near equimolar ratio。 This multi-master high entropy alloy elements are easy to promote the formation of simple mixing elements of body-centered cubic or face-centered cubic structure。 It also has a certain compound of the intergranular phase which can provide a good dispersion strengthening or solid solution strengthening。 Thus, many high entropy alloys may exhibit higher strength, hardness, wear resistance, corrosion resistance and so on。

In this paper, we study three high-entropy alloys via alloying: Sn-Bi-Ag-In-Sb, Sn-Bi-In-Sb-Ge and Sn-Bi-In-Sb-Ga。 The melting process were investigated to observe the forming abilities of the three alloys。 The phase and the elements produced during the solidification can be speculated and tested by OM and SEM; The heat absorption characteristics and the melting point can be observed during the heating and cooling process by differential scanning calorimetry(DSC); The tensile properties of the alloys can be tested by stretching test, then we can observe the deformation and fracture。

We get the following conclusions: (1)The high-entropy alloy contains five elements which are the Sn, Bi, In, Sb and Ag。 It smelts eventually formed six major components of the organization which are InSb, InAg3, Ag4Sn, Sn, Ag3Sb and Ag3Sn。 Sn-Bi-In-Sb-Ge high-entropy alloy mainly contains the following components: Sn, Ge and InSb。 Sn-Bi-In-Sn-Ag  alloy  is  consist  of  amorphous  matrix  and  the  BiIn  crystalline phase。

However，the Bi phase can not be found in the first two alloys because other elements may

be dissolved in the Bi phase。 That make pure bismuth into bismuth-rich phase which cause a lattice distortion and the lattice distortion results in a larger lattice diffraction peaks deviate。 The Bi phase may rely on a phase and form a small amount of intermetallic compound which is less than a detectable amount。 Because of that, the Bi phase cannot be found by XRD。 (2) The organizational structure of Sn-Bi-In-Sb-Ag and Sn-Bi-In-Sb-Ge are  mostly  multiphase  combination。  The  organizational  structure of  Sn-Bi-In-Sb-Ga is