Effects of OSP and Im-Sn surface-finished substrates on microstructure and high speed shear performance of Sn10Sb solder joints
The Sn10Sb alloy,with excellent thermal fatigue properties and relatively high fracture strength,has been widely used in market segments requiring heat fatigue resistance,but the highspeed shear performance of its solder joints under different surface-finished substrates is still lacking in research.The effects of organic solderability pre-servatives(OSP)and immersion-Sn(Im-Sn)surface-finished substrates on the mechanical properties of Sn10Sb(mass fraction of Sb is 10％)solder joints at shear rate of 1 000 mm/s were studied.The results show that com-pared with Sn10Sb bulk alloy,Sn-Sb compounds of 20-40 μm are uniformly dispersed in β-Sn matrix.Due to the un-even thermal field during melting and solidification,the coarse Sn-Sb compounds with the same size are most isolated on the surface,while a few of them gather in the interior and interface of solder joints,which can be explained by uneven distributed thermal field during heating and cooling process using Ansys finite element simulation.In addi-tion,scanning electron microscope(SEM)and energy dispersive X-ray spectroscopy(EDS)were used to observe the solder joints,and it was found that the solder joints of two kinds of surface-finished substrates were both com-posed of β-Sn matrix,SnSb compounds and Cu6 Sn5 compounds.Compared with the microstructure of Sn10Sb/OSP solder joints,Sn10Sb/Im-Sn solder joints have more SnSb compounds and the interface Cu6Sn5 is thinner.This leads to higher shear strength but lower ductility of Sn10Sb/Im-Sn solder joints,resulting in lower shear energy.This study provides a theoretical support for the effects of OSP and Im-Sn surface-finished substrates on microstructure and high-speed shear performance of Sn10Sb solder joints.
Sn10SbOSPIm-SnAnsys finite element simulationhigh speed shearmechanical property
NETL
NSTL
万方数据
维普
