A new creep fatigue model for solder joints. (July 2019)

• Record Type: Journal Article
• Authors: Wong, E.H.
• Is Part Of: Microelectronics and reliability. Volume 98(2019)
• Page Start: 153
• Page End: 160
• Publication Date: 2019-07
• Subjects: Creep fatigue -- Analytical equation -- Temperature cycling -- Accelerated testing -- Acceleration factor; Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2019.05.012
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: The simplicity of the Engelmaier equation is highly attractive; however, it suffers from two critical flaws: (i) it is incapable of modeling the full range of creep fatigue, from pure fatigue to pure creep; and (ii) the embedded creep function is inconsistent with the constitutive equation of creep. As such, the fitting constants in the Engelmaier equation are not material constants but have limited window of applicability. In this manuscript, three novel creep-integrated fatigue equations that are capable of modeling the full range of creep fatigue and that are embedded with the creep constitutive equations of Dorn, Larson-Miller, and Manson-Haferd are established. The equations are validated and benchmarked against the Engelmaier equation using the experimental creep fatigue data of Sn37Pb and An3.5Ag solders. The fitting constants in these creep-integrated fatigue equations are material constants and therefore can be used with confidence to accelerate creep fatigue testing. The acceleration factors for temperature cycle testing of solder joints in electronic assemblies have been established for these novel creep-integrated fatigue equations. Highlights: Novelty: fatigue equation embedded with creep constitutive equation Superior accuracy: validated with creep fatigue data of Sn37Pb and Sn3.5Ag solders; benchmarked with Engelmaier equation Novelty: fitting constants of the equation are material constants, independent of design and test conditions. Usefulness: reliable life prediction for new design; reliable acceleration of temperature cycling test