Tenorite CuO nanoplates, a graphene (G)/CuO nanocomposite and an Al/G/CuO composites were investigated in this paper as potential catalysts for the thermal decomposition of ammonium perchlorate (AP); the most common oxidant used in composite propellant formulations. Tenorite CuO nanoplates and the G/CuO nanocomposite were successfully obtained by a facile hydrothermal method; the Al/G/CuO composite was prepared using physical mixing of the G/CuO nanocomposite and aluminum powder with sonication and dispersion. The catalytic activity of these materials was investigated by thermogravimetric (TG) and differential thermal analysis (DTA). The results of DTA indicated that the three materials ameliorate the thermal decomposition of AP, especially the G/CuO nanocomposite and Al/G/CuO composite, where the high temperature decomposition (HTD) of AP decreases from 432 °C to 325 °C and 315 °C, respectively. Significant decrease in activation energy (E_a) (from 129 kJ mol⁻¹ to 71.47 kJ mol⁻¹ and 56.18 kJ mol⁻¹) was also achieved in the presence of these two materials, showing their strong catalytic activity on the thermal decomposition of ammonium perchlorate.

Molecular dynamics simulations are performed to study thermal properties of bulk iron material and Fe nanoparticles (FNP) by using a ReaxFF reactive force field. Thermodynamic and energy properties such as radial distribution function, Lindemann index and potential energy plots are adopted to study the melting behaviors of FNPs from 300 K to 2500 K. A step-heating method is introduced to obtain equilibrium melting points. Our results show ReaxFF force field is able to detect size effect in FNP melting no matter in energy or structure evolution aspect. Extra storage energy of FNPs caused by defects (0%-10%) is firstly studied in this paper: defects will not affect the melting point of FNPs directly but increase the system energy especially when temperature reaches the melting points.

The densification mechanism of Cu–Al mixed metal powder during a double-action die compaction was investigated by numerical simulation. The finite element method and experiment were performed to compare the effect of the forming method, such as single-action die compaction and double-action die compaction, on the properties of compact. The results showed that the latter could significantly raise the densification rate and were in good agreement with Van Der Zwan–Siskens compaction equation. The effects of the different initial packing structures on the properties of the compact were studied. The results showed that a high-performance compact could be obtained using a dense initial packing structure at a given compaction pressure. Additionally, the effects of the Al content and compaction pressure on the relative density and stress distribution were analyzed. It was observed that, with an increase in the Al content at a given compaction pressure, the relative density of the compact increased, whereas the stress decreased. Furthermore, when the Al content was fixed, the relative density and stress increased with increasing compaction pressure. The relationship between the relative density and the compaction pressure under different friction conditions was characterized and fitted according to the Van Der Zwan–Siskens compaction equation. The influence mechanisms of die wall friction on the compaction behavior were investigated. It was revealed that friction is a key factor that causes the inhomogeneity of the powder flow and stress distribution. Finally, the effects of the dwell time and height–diameter ratio on the densification behavior were analyzed, and it was found that an increase in the dwell time promoted the densification process, whereas an increase of the height–diameter ratio could hinder the process.