THE EFFECT OF MECHANICAL CONSTRAINT ON THE FLOW AND FRACTURE OF 63 37-SN/PB EUTECTIC ALLOY/

Copper compact tension specimens containing joints of 63/37 Sn/Pb eute ctic solder alloy are used to study experimentally the flow and fractu re behavior of eutectic solder under conditions of monotonic loading a nd mechanical constraint. Such constraint arises naturally due to the presence of the specimens' copper/solder interfaces, and various level s of constraint are achieved by employing joints of various sizes. Con comitant finite element analyses of the compact tension experiments ar e performed in which the solder is characterized by the phenomenologic al viscoplasticity model of Bodner and Partom. These experimental and analytical results, along with electron microscopy of the failure surf aces, clearly demonstrate the interplay between plastic Bow, mechanica l constraint, and microscopic characteristics of copper/solder interfa ces, in the overall response of, and failure initiation in, these comp osite specimens.