Effect of cooling rate on the room-temperature indentation creep of cast lead-free Sn-Bi solder alloys

✍ Scribed by Mahmudi, R. ;Geranmayeh, A. R. ;Mahmoodi, S. R. ;Khalatbari, A.

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 418 KB
• Volume: 204
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200622583

✦ Synopsis

Abstract

The influence of cooling rate on the creep behavior of cast Sn–(1–5)%Bi solder alloys was studied by indentation testing at room temperature. The alloys were prepared at two different cooling rates of 0.01 Ks^–1^ and 8 Ks^–1^. This affected the microstructure and thus, the creep behavior of the materials. The stress exponents were found to be about 9.5 and 14.5 for slowly cooled (SC) and fast cooled (FC) conditions, respectively. For a given level of Bi, the FC samples with the Bi mainly in solid solution were more creep resistant than the SC conditions. The lower creep resistance of the SC materials can be explained by the massive precipitation of Bi particles, which tend to segregate as a network in the matrix of the material. This leaves less Bi in solid solution and thus, weakens the hardening mechanism and decreases the creep resistance of these soft solder alloys. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)