Joining Metals Using Semi-Solid Slurries

A method of joining metals with semi-solid slurries is presented. Experiments have been carried out using a model alloy of Sn-Pb to demonstrate the concept. The advantages of this process are a controlled microstructure of the weld, lower post-welding stresses and a small heat affected zone. Tensile tests have been performed, showing a weld strength comparable to bulk material strength. Key factors in this process are the substrate and slurry temperature as well as the absence of superficial oxides or contaminants. The substrate must be preheated locally before the slurry fills the weld groove so that the portion of the substrate in contact with the oncoming slurry is also in the semi-solid state. The process described here has a patent pending in the U.S. Office of Patents and Trademarks. Thesis Supervisor: Stuart B. Brown Title: Richard P. Simmons Associate Professor of Materials Manufacturing