کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
549363 | 872362 | 2011 | 6 صفحه PDF | دانلود رایگان |
Rare-earth-containing Pb-free solders have gained widespread attention due to their superior ductility relative to conventional Pb-free alloys. Our previous work has shown that new Ce-based alloys are also extremely oxidation resistant compared to La or Y-containing alloys. In this paper, we report on a mechanism-based model for the large increases in ductility with small addition of rare-earth element to Sn–3.9Ag–0.7Cu. The mechanisms of ductility enhancement by Ce were observed in a scanning electron microscope, in interrupted shear-tests, where CeSn3 particles served as microscopic fracture and void nucleation sites. Micro-mechanical modeling using the finite-element method was used to examine the plastic strain field in solder affected by the particles. The concentrated deformation band was seen to be disturbed by the particles, resulting in a more uniform deformation pattern with reduced strains and thus enhanced ductility of the lap-sheared joint.
Journal: Microelectronics Reliability - Volume 51, Issue 6, June 2011, Pages 1142–1147