This study systematically optimizes the synthesis parameters for nano‐enhanced phase‐change materials (NEPCMs) based on paraffin wax and copper oxide. The objective is to collectively improve both thermal conductivity and latent heat capacity. Unlike the previous research, the present approach considers all significant synthesis parameters simultaneously, employing a fractional factorial approach for efficient experimentation. By varying CuO nanoparticle sizes, paraffin wax melting temperatures, and mass fractions of CuO and surfactant in pure paraffin wax, the comprehensive thermal analysis reveals a maximum enhancement of 51.2% thermal conductivity compared to pure paraffin wax. In addition to thermal conductivity improvement, the applied optimization strategy identifies six NEPCM combinations, collectively enhancing thermal conductivity, latent heat of melting, and solidification. Among these, one NEPCM exhibits notable improvements of 13.39%, 6.9%, and 4.5% in thermal conductivity, latent heat of melting, and solidification, respectively, making it suitable for thermal energy storage systems due to combined enhanced thermal properties. Additionally, the ANOVA approach indicates the melting temperature of pure PCM as the most significant factor for thermal conductivity enhancement, with a contribution of 55.45%. The present study has a direct impact on improving thermal properties, specifically in thermal energy storage technology, making it relevant to the thermal management research community.

This research article presents a comprehensive study on the prediction of thermal conductivity (TC) as a primary outcome for an artificial neural network (ANN) model in the context of nanoenhanced phase change materials (NEPCMs). To improve predictive accuracy and to reduce variation within the NEPCM dataset, a targeted dataset was employed, consisting exclusively of NEPCMs synthesized using paraffin wax (PW) and metal oxide nanoparticles. Unlike existing empirical models that predict TC of NEPCM without simultaneously considering multiple factors influencing it, this study integrates multiple factors, providing a more accurate prediction of NEPCM thermal conductivity. Additionally, the study explores the impact of synthesis parameters on the thermal performance of NEPCMs, focusing on the examination of factors such as the melting temperature of pure phase change material (PCM), nanoparticle size, and NEPCM composition. The thermal characterizations demonstrate outstanding thermophysical properties in NEPCMs, particularly in terms of thermal conductivity, phase change enthalpy, and thermal stability compared to their respective base PCM. An ANN TC prediction model demonstrates exceptional correlation (>99%) with reported NEPCMs, providing a reliable tool for TC forecasting in similar NEPCM categories. The backpropagation ANN model predicts NEPCM TC with a mean squared error (MSE) of 0.031124 within eight epochs. The dataset used exhibits high fit values, with R‐values of 0.99825, 0.99208, and 0.9824 for training, validation, and testing, respectively. These values closely match experimentally determined TC, with less than 4% error.

In this study, TiC-reinforced CoCrFeMnNi high-entropy alloy (HEA) composites were prepared by mechanical alloying (MA) and spark plasma sintering (SPS). The phase composition, microstructure, mechanical and thermal expansion behaviour of composite HEAs were investigated. The results reveal that the addition of TiC has no effect on the crystal structure, however, the microstructure and mechanical properties show a strong dependency on the TiC content. Compared to the original HEA, the composite HEA shows decreased grain size, resulting in TiC nanoparticles (NPs) retarding grain growth by pinning the grain boundaries. With increasing TiC content from 0 to 4 wt-%, significant increases in the hardness from 410 to 480 HV and compressive yield strength from 680 to 1100 MPa, which is mainly due to the grain boundary and dispersion strengthening effects. Moreover, the thermal expansion curves show linear increments up to 800°C and decrease with increasing TiC content.