Evolution and formation of dissimilar metal interface s in fusion welding

The evolving interface forms between two different liquids during dissimilar
metal welding can critically influence the development of the as solidified microstructure and determine the mechanical properties of the joint. To investigate the interface evolution mechanisms during arc welding , time resolved X radiography was employed. The observations reveal the formation of transient finger like protrusions at the dissimilar liquid interface prior to a brief, quasi steady state. The analysis of the experimental observations using the magneto thermal hydrodynamic numerical simulations confirms that the quasi steady state involves the formation of a short lived solid phase, which alters the regular mixing during the process. A nalysis of the in situ experimental observations elucidate the interactions between thermal, momentum, electromagnetic and compositional fields which determine mechanisms of formation of the liquid interface instabilities and the melt pool shape. Based on the analysis , we extended our study to offer practical enhancement for dissimilar welding through offsetting the heat source.