The Department of Materials Science and Engineering is pleased to announce that research under Dr. Donald Brenner and Dr. Douglas Irving has been selected to be part of Modelling and Simulation in Materials Science and Engineering\’s Highlights of 2010 Collection. The group\’s research will be one of ten carefully selected papers, some containing outstanding research and breakthroughs, some with especially clear exposition and beautiful presentation, and others that are instructive, with tools useful to many readers.
The group\’s paper, titled \”Atomic and multi-scale modeling of non-equilibrium dynamics at metal-metal contacts\’, has been amongst the most frequently downloaded from the journal website in the past year and exemplifies the high standard of research expected by the MSMSE.
The collection is free to read throughout 2011 from the following link:
A coarse graining method that introduces Joule heating and improves heat transport in a classical molecular dynamics simulation is reviewed, and two example sets of simulations, opening of gold-gold nano-asperity contacts and nano-asperity sliding at loaded copper-aluminum interfaces are discussed. For the gold contact, dislocations nucleate from the edges of where the asperity contacts the substrates and move along the close-packed planes, resulting in stacking faults that form two subsurface Thompson tetrahedra. For a null voltage, a nanowire with a diameter much smaller than the initial contact area is created when the two tetrahedra are completed, and as the wire yields the partial dislocations retreat to the surface. Opening with Joule heating enhances dislocation mobility and intransient subsurface plasticity. Constant current simulations show melting and boiling of the nanowires depending on the voltage cap. Sliding of an aluminum asperity on copper iwth a null voltage shows dislocation formation in the copper and aluminum, while heating from an applied voltage eliminates damage in the coppper. Sliding with a copper asperity enhances plastic damage in the copper substrate compared with the aluminum asperity, while Joule heating enhances aluminum pile-up in front of the copper asperity due to plowing.