| Abstract Scope |
Compression creep testing was conducted on the lead (Pb)-free solder alloy “Violet” (Sn-2.25Ag-0.5Cu-6.0Bi). Testing was conducted at one of four temperatures (-25°C, 25°C, 75°C, or 125°C). A applied load of either 5MPa, 10MPa, 15MPa, 25MPa, 30MPa, 40MPa, or 50MPa was used, and samples were tested in either as-fabricated conditions or after aging (125°C for 24 hours). Three samples of each set of variables were tested, according to the ASTM E9 standard. Tests were halted after either two days had elapsed, or the sample reached a strain of 0.12.
Strain-time curves were used to determine steady-state creep strain rate, allowing for analysis of creep deformation kinetics. The results from this testing, along with planned time-independent (stress-strain) testing, will allow for the development of a constitutive thermomechanical model. This is a necessary step towards the commercialization of the alloy and adoption by the industry as a viable Pb-free alloy solution. |