creep behavior of a sn-ag-bi pb-free solder蠕变行为的sn-ag-bi pb-free焊料.pdfVIP

Materials 2012, 5, 2151-2175; doi:10.3390/ma5112151 OPEN ACCESS materials ISSN 1996-1944 /journal/materials Article Creep Behavior of a Sn-Ag-Bi Pb-Free Solder Paul Vianco *, Jerome Rejent, Mark Grazier and Alice Kilgo Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185, USA; E-Mails: jarejen@ (J.R.); jmgrazi@ (M.G.); ackilgo@ (A.K.) * Author to whom correspondence should be addressed; E-Mail: ptvianc@; Tel.: +1-505-844-3429; Fax: +1-505-844-4816. Received: 28 July 2012; in revised form: 27 September 2012 / Accepted: 18 October 2012 / Published: 2 November 2012 Abstract: Compression creep tests were performed on the ternary 91.84Sn-3.33Ag-4.83Bi (wt.%, abbreviated Sn-Ag-Bi) Pb-free alloy. The test temperatures were: −25 °C, 25 °C, 75 °C, 125 °C, and 160 °C (± 0.5 °C). Four loads were used at the two lowest temperatures and five at the higher temperatures. The specimens were tested in the as-fabricated condition or after having been subjected to one of two air aging conditions: 24 hours at either 125 °C or 150 °C. The strain-time curves exhibited frequent occurrences of negative creep and small-scale fluctuations, particularly at the slower strain rates, that were indicative of dynamic recrystallization (DRX) activity. The source of tertiary creep behavior at faster strain rates was likely to also be DRX rather than a damage accumulation mechanism. Overall, the strain-time curves did not display a consistent trend that could be directly att