Effect of geometry on the fracture behavior of lead-free solder joints

Siva P.V. Nadimpalli, Jan K. Spelt

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Copper bars were soldered along their length with a thin layer of lead-free Sn3.0Ag05.Cu alloy under standard surface mount processing conditions to prepare double cantilever beam (DCB) specimens. The geometry of the DCBs was varied by changing the thickness of the solder layer and the copper bars. These specimens were then fractured under mode-I and two mixed-mode loading conditions. The initiation strain energy release rate, Gci, increased with the relative fraction of mode-II, but was unaffected by the changes in either the substrate stiffness or the solder layer thickness. However, the steady-state strain energy release rate, realized after several millimeters of crack growth, was found to increase with the solder layer thickness at the various mode ratios. The crack path was found to be influenced by mode ratio of loading and followed a path that maximizes the von Mises strain rather than maximum principal stress. Finally, some preliminary results indicated that the loading rate significantly affects the Gci.

Original languageEnglish (US)
Pages (from-to)1169-1181
Number of pages13
JournalEngineering Fracture Mechanics
Volume78
Issue number6
DOIs
StatePublished - Apr 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Keywords

  • Crack path
  • Fracture
  • Lead-free solder
  • Loading rate
  • Mixed-mode
  • R-curve
  • Stiffness
  • Strength
  • Thickness

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