Characterization of strain-rate sensitivity of Sn-5%Sb solder using ABI testing

A thorough knowledge of the mechanical and fracture properties of solder materials is required both for life-prediction and alloy development. Often only a limited amount of material is available precluding the usage of full-size specimens and thus hardness testing is usually resorted to, which, however, would not give the full stress vs strain characteristics. Whereas, these stress vs strain characteristics can be obtained using the ball indentation. We applied the recently developed Automated Ball Indentation (ABI) testor to evaluate the strain-rate-sensitivity (SRS) of Sn5%Sb solder material at room temperature by varying the indentor velocity over three orders of magnitude. Constant load creep tests were also performed on the same material which covered the low strain-rate range and were in good agreement with ABI. The tensile test results exhibited slight deviation albeit in reasonable agreement with creep and ABI data. While power-law stress dependence is observed at low stresses, results at high (greater than or equal to 1.2x10(-3)E) stresses followed an exponential law charactetized by an activation area of similar to 100b(2). The underlying deformation micromechanism is discussed.