A solder alloy includes Sn, optional Ag, Cu, and Al wherein the alloy composition is controlled to provide a strong, impact-and thermal aging-resistant solder joint that has beneficial microstructural features and is substantially devoid of Ag.sub.3Sn blades.
CONTRACTUAL ORIGIN OF THE INVENTION
 This invention was made with government support under Contract No. DE-AC02-07CH11358 awarded by the U. S. Department of Energy. The government has certain rights in the invention.