Abstract
Obtaining detailed information regarding the interfacial characteristics of metal/hexagonal-TMN composites is imperative for developing these materials with optimal mechanical properties. To this end, we systematically investigate the work of adhesion, fracture toughness, and interfacial stability of M/Cr2N and M/V2N interfaces using first-principles calculations. The orientation (0001) of hexagonal phases and (111) of fcc phases are selected as the interface orientations. Accordingly, we construct M/Cr2N interface models by considering 1N, 2N, and Cr terminations of Cr2N(0001), as well as two stacking sequences (top and hollow sites) for the 1N- and 2N-terminated interface models, respectively. The M/V2N interface models are constructed in the same way. The V-terminated Ni/V2N interface is demonstrated to provide a good combination of the work of adhesion, fracture toughness, and interfacial stability. Therefore, the Ni/V2N interface model can be regarded as the preferred configuration among the metal/hexagonal-TMN interface models considered. The present results offer a practical perspective for tailoring the interfaces in metal/hexagonal-TMN composite materials to obtain improved mechanical properties.
Highlights
Metal/transition metal nitride (TMN) composite materials can have good mechanical and tribological properties, because they combine the ductility and hardness provided by soft metal and hard ceramic, respectively [1,2,3]
The M/Cr2N and M/V2N interface models were built in the same way because th lattice constants of Cr2N and V2N are approximate
The results show that: (i) both the Ru/Cr2N-Cr and Ru/V2N-V interface models have larger values of KIC-metal than the values of KIC-ceramic, which is determined by the considerably large value of E0001 obtained for Ru; (ii) the Ni/Cr2N-Cr interface model has a larger value of KIC-metal than the value of KIC-ceramic, which is because the value of E111 obtained for Ni is larger than the value of E0001 obtained for V2N; (iii) except Ru/Cr2N-Cr, Ni/Cr2N-Cr, and Ru/V2N-V, the other interface models have the larger value of KIC-ceramic than the value of KIC-metal
Summary
Metal/transition metal nitride (TMN) composite materials can have good mechanical and tribological properties, because they combine the ductility and hardness provided by soft metal and hard ceramic, respectively [1,2,3]. DFT calculation has been demonstrated to be a powerful method for revealing detailed information regarding atomic and electronic structures at the interfaces between two phases, thereby facilitating predictions regarding the stability, adhesion strength, and fracture toughness of interfaces [22,23,24]. First-principles calculation based on DFT has developed to become one of the most frequently used theoretical methods for revealing the interfacial properties of metal/ceramic composites. For the metal/TMN systems considered in this work, previous theoretical studies based on DFT focused their attention on interfacial configuration, stability and bonding strength of metals/cubic TMN interfaces, such as α-Fe/CrN [25], Ni/CrN [26], Cu/TiN [27], and Al/VN [28]. We calculated interfacial work of adhesion of the M/Cr2N and M/V2N interface models, and determined the optimal one with the strongest bonding strength. The convergence tolerances were set as 1.0 × 10−5 eV/atom for the energy, 0.03 eV/Å for the maximum force, and 0.001 Å for the maximum displacement
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
