This study investigated the metal forming of magnesium alloy plates using dynamic load, which is referred to as explosive forming. Cold metal working is difficult to perform on magnesium alloys using typical metal forming methods. Therefore, this study used explosive forming technique with a convex die. This is one of the metal forming technologies equipped with a special forming mechanism. The desired forming result was obtained by controlling the pressure wave applied to plates when the inclination of the die was steep, that is, the amount of deformation was large. In addition, the control of the pressure wave was investigated through numerical simulation.
In order to change the energy release properties of energetic materials by altering the electronic state, the electrolytic oxidation of azoles with sodium perchlorate was carried out at conditions determined by linear sweep voltammetry. The change in electronic state due to the electrolytic oxidation was verified using ultraviolet spectroscopy. The thermal stability of products was investigated using sealed cell differential scanning calorimetry and thermogravimetricdifferential thermal analysis. The electrolytic oxidation provided products whose onset temperatures of peaks differed from those of reactant azoles. The electrolytic oxidation destabilized 1,2,4-triazole (TA) and 4-amino-1,2,4-triazole (4ATA), but increased the stability of 3-amino-1,2,4-triazole (3ATA). However, distinct exothermic peaks were observed and QDSC significantly increased for all triazole products. The gasification rates increased by more than 50 % due to electrolytic oxidation. In particular, electrolytic oxidized TA with perchlorate reached 99.5 % of gasification rate. These results confirmed that electrolytic oxidation is a promising method for developing new energetic materials with favorable energy release properties.
When metal is cut and ground with a grinder, chips are heated by friction and oxidation, and scattered, which look like sparks. The temperature varies depending on the particle properties with changing in time accordingly. It is difficult to obtain quantitative information simultaneously such as each particle size, unsteady velocity, and temperature varying over 1000 K. In the present study, we developed a new framework for estimating the particle size of pure iron sparks by fitting the equation of motion to the trajectory of the time-resolved images, and for calculating the spark temperature by solving the unsteady thermal equation. The validity is convinced through the comparison with the high-speed images, SEM images, and temperature measurement results. We succeeded in finding the time-dependent changes in temperature and heat balance, which are closely related to the colors of sparks, starting from the grinder to the end. The heat production by surface oxidization deteriorates as the spark decelerates due to the aerial drag force. The heat dissipation of heat transfer is dominantly affected by the spark temperature rather than the boundary layer thickness. The effect of the heat of fusion is insignificant in the temperature change.
The Al/α-AlH3 was prepared in ether solution with LiAlH4 and AlCl3 with some addition. The crystallization and the morphology of the prepared samples were studied by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The organic elemental analyzer can be used to determine the content of H element. Furthermore, the effects of Al on the thermal stability and security of α-AlH3 were also studied. The thermal stability has been studied by TG curves. The impact sensitivity test, friction sensitivity test and electrostatic spark sensitivity test have been tested. The results shown that the existence of the Al has no impact on the friction sensitivity, impact sensitivity of pure α-AlH3. However, the existence of Al increases the decomposition rate of α-AlH3.