Influence of small addition of antimony (Sb) on thermal behavior, microstructural and tensile properties of Sn-9.0Zn-0.5Al Pb-free solder alloy

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Date

2017

Journal Title

Journal ISSN

Volume Title

Type

Article

Publisher

ELSEVIER SCIENCE SA.

Series Info

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING;Volume: 701 Pages: 245-253

Abstract

Eutectic Sn-Zn alloy is considered as one of the best lead free solder alloys in microelectronic industry. That motivates our group to select different weight percentage of Antimony (Sb) (0.5, 1.0, and 1.5 wt%) as an alloying to Sn-9.0Zn-0.5 Al solder alloy. The thermal behavior, microstructure modification as well as tensile properties of the new developed solder alloys were investigated. A slight increment of the melting temperature (similar to 1 degrees C) was recorded using differential scanning calorimetry (DSC) after additions of Sb. For 1.5 wt% of Sb, two endothermic peaks at 200.8 degrees C and 201.5 degrees C were observed, which are assigned as hypoeutectic Sn-Zn composition. X-ray diffraction (XRD) measurements confirm the existence of beta-Sn phase, alpha-Zn phase, and Sb-Sn intermetallic compounds (IMCs). Scanning electron microscope (SEM) images indicate that the Sb additives refine the microstructure and form a uniform distribution of IMCs in the matrix of solder. The road-like alpha-Zn phase, Al6Zn3Sn and SbSn IMCs were clearly appeared in beta-Sn matrix, which are responsible of the enhancement in tensile strength. Moreover, alpha-Zn phases in the Sn-9Zn-0.5A1-1.5Sb alloy were modified as needle-like, broken enormously, depleted, and circle shapes. Generally, The Sb-containing alloys have higher ultimate tensile strength (UTS) and lower elongation than Sb-free solder alloy due to the solid solution and second phase dispersion strengthening effect. The relationship between UTS and temperature follow the Arrhenius law. The average activation energies (Q) were found to be 44.4 +/- 1.0 kJ/mol, and the average stress exponents (n) were usually around 5.3 +/- 0.45, which are close to pipe diffusion controlled creep in beta-Sn matrix.

Description

Accession Number: WOS:000406989000027

Keywords

University of Sn-Zn-A-Sb alloys; Lead-free solder; Microstructure; Thermal properties; Tensile strength; Mechanical properties, LEAD-FREE SOLDER; ZN EUTECTIC ALLOY; CREEP-PROPERTIES; AL SOLDER; SN; AG; CU; INTERFACE; JOINTS; GA

Citation

Cited References in Web of Science Core Collection: 48