Time dependent crack growth in soldered joint

Abstract Time dependent crack growth in a soldered joint, 60/40 Sn/Pb and unplated, silver plated and gold plated beryllium copper, is experimentally investigated. Double cantilever beam specimens selected for the test are machined by wire EDM with the center split deeply cut almost clear to one end. This center slit is then soldered by vapor phase reflow after depositing the solder paste. After creating an initial crack in the solder layer, a subcritical load in the opening mode is applied and the corresponding displacement at the loading point is held constant. Subsequent load decrease and increase in the crack length are recorded with time. Thus observed rate of crack growth per unit time is found to relate proportionally to the third power of the strain energy release rate. Furthermore, there seems to exist a threshold strain energy release rate of 200–300 J/m 2 under which no crack growth is observed.