Effect of Gold Addition on the Microstructure and Mechanical Properties of Sn–3.8Ag–0.7Cu Lead-Free Solder Alloy

• Published in: Transactions of the Indian Institute of Metals Vol. 71; no. 6; pp. 1497 - 1505
• Main Authors: Niranjani, V. L., Venkateswarlu, Pamidi, Singh, Vajinder, Chandra Rao, B. S. S., Kamat, S. V.
• Format: Journal Article
• Language: English
• Published: New Delhi Springer India 01.06.2018; Springer Nature B.V
• Subjects: Alloys; Chemistry and Materials Science; Corrosion and Coatings; Deformation mechanisms; Elongation; Gold; Intermetallic compounds; Lead free; Materials Science; Mechanical alloying; Mechanical properties; Metallic Materials; Microstructure; Powder metallurgy; Strain rate; Technical Paper; Tensile properties; Tin base alloys; Tribology; Mechanical properties; Temperature; SAC 387 lead free solder alloy; Au addition; Strain rate
• ISSN: 0972-2815; 0975-1645
• DOI: 10.1007/s12666-018-1285-0

The effect on mechanical properties and microstructure of SAC 387 lead free solder alloys by addition of 1 wt% Au nanoparticles was studied. Also the effect on tensile properties at different temperatures and strain rates was investigated. The powder metallurgy process followed to make the SAC 387 + 1 wt% Au alloy was found to result in mechanical alloying and complete dissolution of Au in the β-Sn matrix resulting in the formation of fine AuSn 4 intermetallics. The addition of 1 wt% Au to the base alloy SAC 387 resulted in an increase in yield (YS) and ultimate tensile strengths (UTS) at all temperatures and strain rates without any decrease in the total elongation (TE). Both YS and UTS were found to decrease with increase in temperature at any given strain rate for the base alloy SAC 387 as well as SAC 387 + 1 wt% Au alloy. On the other hand, for both alloys, YS and UTS were found to increase with increase in strain rate at any given test temperature. Although the trends in change of uniform elongation (UE) and TE with temperature and strain rate were not as monotonic as in the case of YS and UTS, in general, the UE and TE increased with increasing temperature and decreased with increasing strain rate. The results were explained based on the likely deformation mechanisms operative in these alloys at different strain rates and temperatures.