STP1153: A Model for Primary Creep of 63Sn-37Pb Solder

    Schroeder, SA
    Rockwell International Science Center, Thousand Oaks, CA

    Morris, WL
    Rockwell International Science Center, Thousand Oaks, CA

    Mitchell, MR
    Rockwell International Science Center, Thousand Oaks, CA

    James, MR
    Rockwell International Science Center, Thousand Oaks, CA

    Pages: 13    Published: Jan 1994


    Abstract

    A micromechanical model of transient and steady-state creep as it applies to near eutectic Sn-Pb solder is presented. The material is described as a two-phase system having individual material properties, coupled by long-range internal stresses. The constitutive equations permit primary creep and the transition to steady state to be simulated by a numerical analysis in which the global mechanical response is dependent on the local stress state.

    The creep equations are calibrated through a series of shear strain measurements of thinwalled tubular solder specimens. Comparisons to predictions include cyclic shear straincontrolled experiments, creep relaxation, and combination ramp-hold shear strain and stress control environments. Application to finite element analysis of surface mount interconnects is described.

    Keywords:

    63Sn-37Pb solder, primary creep, steady-state creep, thin-walled tube, torsion, shear, composite model, finite element methods


    Paper ID: STP23917S

    Committee/Subcommittee: E08.05

    DOI: 10.1520/STP23917S


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