Thermal expansion behavior of nickel nanocomposites reinforced with titanium diboride submicron particles and graphene nanoplatelets: Numerical prediction and statistical analysis

This study reports the development of a robust predictive model for estimating the coefficient of thermal expansion (CTE) of nickel-matrix nanocomposites containing titanium diboride (TiB 2 ) particles and graphene nanoplatelets (GNPs). To this end, the morphology-centric computational simulation, established through micromechanical modeling and subsequently coupled with finite element analysis, is employed to replicate the diverse microstructural configurations of the three-phase nanocomposite. The representative volume elements (RVEs) are generated in a novel manner, wherein the TiB 2 particles are modeled as 20-faced polyhedra comprising two hexagonal faces, twelve trapezoidal faces formed through dual truncations, and six rectangular lateral faces, while the GNPs are represented as hexagonal platelets. Systematic numerical and statistical assessments of the governing factors influencing the CTE of the proposed ternary nanocomposite primarily focus on the morphology of the reinforcing phases, reinforcement-matrix interactions, and the presence of microstructural defects. The results indicate that achieving a system with an acceptable CTE is feasible, provided that uniform dispersion is ensured, finer TiB 2 particles and thinner GNPs are utilized, reinforcement phase alignment is attained, coherent interphase engineering is implemented, and both void formation and agglomeration of TiB 2 particles and GNPs are effectively prevented.