Low Cycle Fatigue Lives of Sn-37Pb and Sn-3.5Ag Solders at Low Temperatures
Noritake HIYOSHI, Akihisa KATOH, Masao SAKANE and Yutaka TSUKADA
Abstract:This paper describes low cycle fatigue lives of Sn-37Pb and Sn-3.5Ag solders at low temperatures. Push-pull low cycle fatigue tests were carried out at 253K and 273K to study the temperature effect on low cycle fatigue life. Plastic strain range was a suitable parameter for correlating the low cycle fatigue lives for the Sn-37Pb solder at the four temperatures but it was not for the Sn-3.5Ag solder. Strain energy parameter which is defined as the product of strain and stress ranges was a suitable parameter for the Sn-3.5Ag solder. Application of universal slope method was also discussed for predicting the low cycle fatigue lives of Sn-37Pb and Sn-3.5Ag solders. Key Words:Lead-free solder, Low cycle fatigue, Low temperature, Stress-strain relationship, Life evaluation, Cracks