電子機器用はんだ材料の疲労寿命評価法(<小特集>信頼性工学小特集)

概要

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In order to clarify the effect of cycling frequency on the fatigue life of solder, strain controlled fully reversed torsional fatigue tests were carried out on thin-walled cylinder type 60Sn-40Pb solder specimens under six strain cycling frequencies of 0.001, 0.01, 0.03, 0.05, 0.5 and 1.0 Hz at 303K. The results obtained in this study are summarized as follows : (1) As a general strength trend of the solder, the lower was the strain cycling frequency the shorter was the fatigue life. But, the solder showed an opposite strength trend in the inelastic strain range exceeding about 1.4 %, presumably depending on the creep effect. (2) Two different expressions were constructed to evaluate the fatigue life of the solder under relatively high cycling frequencies over 0.03 Hz, and under all cycling frequencies (0.001〜1.0 Hz), respectively. The expression for the former case was constructed on the basis of the Coffin's frequency modified fatigue life estimation method. And the expression for the latter case was a general one constructed by using the strain-range partitioning approach and linear cumulative damage concept to take account of the superposed effect of both plastic and creep deformations. The fatigue lives estimated by the above two expressions coincided well with the corresponding experimental results.
社団法人日本材料学会の論文
1992-07-15