Atomistic Calculations of Interface Properties for Co-Al-W Alloys

With an increasing need for large-scale atomistic simulations on Co-Al-W systems, one needs an interatomic potential model that can describe all the constituent elements and their alloy systems simultaneously using a common mathematical formalism. The Second-Nearest-Neighbor Modified Embedded-Atom Method (2NN MEAM)-a semi-empirical inter-atomic potential formalism, has been applied to obtain interatomic potentials for ternary Co-Al-W system based on the previously evaluated potentials for pure Co, Al and W and binary systems- Co-Al, Co-W an Al-W. The values of fundamental physical properties for the ternary Co-Al-W system generated by using the new potentials are relatively accurate. The enthalpy of formation, the thermal stability and the elastic constants match well with experimental and the first-principles results. The formation energy of L1 2 -Co 3 Al 0.05 W 0.05 structure is smaller than that of the DO 19 -Co 3 Al 0.05 W 0.05 structure. The potentials can be easily combined with already-developed MEAM potentials to describe Co-Al-W multicomponent systems and can be utilized for an atomistic computation to the elaborate alloy design of advanced Co-Al-W superalloys through the investigation of the interfacial properties (the interfacial energy and the work of separation). Results showed that Al additions increase the interfacial energy and lower the work of separation while W additions lower the interfacial energy and increase the work of separation.