Title :
Influence of temperature on low cycle fatigue and fatigue crack growth of Sn-Ag eutectic solder
Author :
Kanchanomai, C. ; Mutoh, Y.
Author_Institution :
Dept. of Mech. Eng., Thammasat Univ., Pathumthani, Thailand
Abstract :
Low cycle fatigue tests on as-cast Sn-Ag eutectic solder (96.5Sn-3.5Ag) were carried out using the non-contact strain controlled system at 0.1 Hz with various temperatures (20, 85, 120°C). The low cycle fatigue behavior in this temperature range followed the Coffin-Manson equation. The fatigue ductility coefficient was found to be influenced by temperature. Ductility-modified Coffin-Manson could not describe temperature effects on the fatigue behavior. Steps at the boundaries of Sn-dendrites were the initiation sites for microcracks for all temperatures studied. The link up of these cracks and the crack propagation inside the specimen occurred both transgranularly through Sn-Ag eutectic phase and/or Sri dendrite, and intergranularly along Sn-dendrite boundaries. Propagation of stage II crack for different temperatures could be characterized by C*-parameter.
Keywords :
eutectic alloys; fatigue cracks; microcracks; silver alloys; solders; surface mount technology; thermal stress cracking; tin alloys; Coffin-Manson equation; Sn-Ag; as-cast eutectic solder; dendrite boundaries; fatigue crack propagation; fatigue ductility coefficient; hysteresis loops; low cycle fatigue tests; microcrack initiation sites; surface mounting technology; temperature effects; thermally-induced fatigue; Capacitive sensors; Electronic packaging thermal management; Electronics packaging; Fatigue; Mechanical engineering; Surface cracks; Surface-mount technology; System testing; Temperature distribution; Tensile strain;
Conference_Titel :
Electronics Packaging Technology, 2003 5th Conference (EPTC 2003)
Print_ISBN :
0-7803-8205-6
DOI :
10.1109/EPTC.2003.1271545
