TENSILE, CREEP, AND ABI TESTS ON SN5-PERCENT-SB SOLDER FOR MECHANICALPROPERTY EVALUATION

Sn5%Sb is one of the materials considered for replacing lead containin g alloys for soldering in electronic packaging. We evaluated the tensi le properties of the bulk material at varied strain-rates and temperat ures (to 473K) to determine the underlying deformation mechanisms. Str ess exponents of about three and seven were observed at low and high s tresses respectively, and very low activation energies for creep (abou t 16.7 and 37.7 kJ/mole) were noted. A maximum ductility of about 350% was noted at ambient temperature. Creep tests performed in the same t emperature regime also showed two distinct regions, albeit with slight ly different exponents (three and five) and activation energy (about 5 4.4 kJ/mole). Ball indentation tests were performed on the shoulder po rtions of the creep samples (prior to creep tests) using a Stress-Stra in Microprobe(R) (Advanced Technology Corporation) at varied indentati on rates (strain-rates). The automated ball indentation (ABI) data wer e at relatively high strain-rates; however, they were in excellent agr eement with creep data, while both these results deviated from the ten sile test data. Work is planned to perform creep at high stresses at a mbient and extend ABI tests to elevated temperatures.