Fatigue and thermal fatigue of Pb-Sn solder joints

Conference · Thu Jan 01 04:00:00 EST 1987

OSTI ID:6187307

Frear, D; Grivas, D; McCormack, M; Tribula, D; Morris, Jr, J W

This paper presents a fundamental investigation of the fatigue and thermal fatigue characteristics, with an emphasis on the microstructural development during fatigue, of Sn-Pb solder joints. Fatigue tests were performed in simple shear on both 60Sn-40Pb and 5Sn-95Pb solder joints. Isothermal fatigue tests show increasing fatigue life of 60Sn-40Pb solder joints with decreasing strain and temperature. In contrast, such behavior was not observed in the isothermal fatigue of 5Sn-95Pb solder joints. Thermal fatigue results on 60Sn-40Pb solder cycled between -55/sup 0/C and 125/sup 0/C show that a coarsened region develops in the center of the joint. Both Pb-rich and Sn-rich phases coarsen, and cracks form within these coarsened regions. The failure mode 60Sn-40Pb solder joints in thermal and isothermal fatigue is similar: cracks form intergranularly through the Sn-rich phase or along Sn/Pb interphase boundaries. Extensive cracking is found throughout the 5Sn-95Pb joint for both thermal and isothermal fatigue. In thermal fatigue the 5Sn-95Pb solder joints failed after fewer cycles than 60Sn-40Pb.

• Research Organization: Lawrence Berkeley Lab., CA (USA)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 6187307
• Report Number(s): LBL-22837; CONF-870272-6; ON: DE87012881
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
CRYSTAL STRUCTURE
FATIGUE
JOINTS
LEAD ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
SOLDERED JOINTS
THERMAL CYCLING
THERMAL FATIGUE
TIN ALLOYS