Title :
Microstructural evolution and mechanical properties of Sn-Bi based solders
Author :
Raeder, C.H. ; Felton, L.E. ; Knorr, D.B. ; Schmeelk, G.B. ; Lee, D.
Author_Institution :
Mater. Eng. Dept., Rensselaer Polytech. Inst., Troy, NY, USA
Abstract :
An overview of issues relevant to reliability of Sn-Bi solder joints is presented. The effects of aging on the microstructure of Sn-Bi solder joints are described. The results show that during aging, Sn is depleted from the solder/base metal interface. The two-phase Sn-Bi microstructure coarsens appreciably during aging. The rate of coarsening can be slowed by adding 1.0 wt% Cu to the solder. Aging also affects the mechanical properties of the solder joints in shear, where aged joints shown an increase in flow stress and plastic strain at failure. The creep properties of cast and aged Sn-Bi eutectic alloy at stresses between 0.5 and 65 MPa and temperatures between 30°C and 120°C are described. In the power law creep regime, cast Sn-Bi eutectic has a stress exponent of three and an activation energy of 0.6 eV
Keywords :
ageing; bismuth alloys; creep; crystal microstructure; ductility; eutectic alloys; plastic deformation; plastic flow; reflow soldering; reliability; shear strength; tin alloys; wave soldering; 0.5 to 65 MPa; 30 to 120 C; SnBi solder joints; SnBi-Cu; activation energy; creep properties; effects of aging; eutectic alloy; failure; flow stress; mechanical properties; microstructural evolution; plastic strain; power law creep regime; rate of coarsening; reliability; stress exponent; two-phase microstructure; Aging; Capacitive sensors; Creep; Mechanical factors; Microstructure; Plastics; Soldering; Stress; Temperature; Tin;
Conference_Titel :
Electronic Manufacturing Technology Symposium, 1993, Fifteenth IEEE/CHMT International
Conference_Location :
Santa Clara, CA
Print_ISBN :
0-7803-1424-7
DOI :
10.1109/IEMT.1993.398212
