Effect of stress and strain state on heterogeneous coarsening in Sn-Pb solder

The effect of three basic stress states on the deformation and heterogeneous coarsening behavior of 60Sn-40Pb is investigated experimentally. Three different initial microstructures are considered. The response of these microstructures under uniaxial compression, pure shear and hydrostatic compression at 125 °C is evaluated on length scales ranging from micrometers to millimeters. Inelastic shear strain concentrations correlate strongly with regions where heterogeneously coarsened bands form. Inelastic deformation precedes accelerated coarsening and damage accumulation at this temperature. Acceleration of coarsening is closely associated with deviatoric strain, while purely volumetric strain has little impact on accelerated coarsening.