Multiscale modeling of metal-metal contact dynamics under high electromagnetic stress: Timescales and mechanisms for Joule melting of Al-Cu asperities

An analysis and initial results from a multiscale continuum-atomistic simulation of the Joule heating and melting of Cu-Al asperity contacts are presented. An analytic expression is given for the time needed to reach the Al melting point for an asperity as a function of the voltage drop and the asperity contact area. The coupled continuum-atomistic simulations capture the initial stages of the formation of Al-Cu alloys, which arises from the sol vation of Cu atoms into the Al melt. The implications of these results for understanding contacts in electromagnetic launchers are discussed.