Experimental Measurement of Vacuum Evaporation of Aluminum in Ti-Al, V-Al, Ti6Al4V Alloys by Electron Beam

Titanium alloys have been widely used in aerospace engineering due to their excellent mechanical properties, especially their strength-to-weight ratio. In addition, Ti6Al4V (TC4) alloy is the most widely used among α+β alloys. The main three elements of TC4 alloy are titanium (Ti), aluminum (Al) and vanadium (V). Since the boiling point of aluminum is much lower than the melting point of the other two elements, the consistency of TC4 alloy during smelting, additive manufacturing and surface treatment is difficult to control. Therefore, in order to study the difficult problem of composition control in TC4 alloy production, we measured the vacuum evaporation of Al, Ti and V in Ti-Al, V-Al and TC4 alloys, and tracked the changes of molten pool temperature, heating time and weight. According to the results, the Al started to evaporate near 1300 ± 10 °C in vacuum and totally evaporated after 225 s heating to 1484 °C at 10−2 Pa. However, V and Ti barely evaporated below 2000 °C. The Al in Ti-Al alloy started to evaporate at 1753 ± 10 °C and lost 20.6 wt.% aluminum during 500 s at 1750~1957 °C. The Al in V-Al alloy started to evaporate at 1913 ± 10 °C and lost 26.4 wt.% aluminum during 543s at 1893~2050 °C. The Al in TC4 alloy started to evaporate at 1879 ± 10 °C and lost 79.6 wt. % aluminum after 113 s at 1879~1989 °C. The results indicate that smelting TC4 alloy with Ti-Al and V-Al alloys by EBM below 1900 °C improves the consistency and performance. Additionally, the lowest loss of Al occurred in the additive manufacturing of TC4 alloy below 1900 °C.

Terahertz Wave Absorption Property of all Mixed Organic–Inorganic Hybrid Perovskite Thin Film MA(Sn, Pb)(Br, I)3 Fabricated by Sequential Vacuum Evaporation Method

All mixed hybrid perovskite (MA(Sn, Pb)(Br,I)3) thin film was fabricated by sequential vacuum evaporation method. To optimize the first layer with PbBr2 and SnI2, we performed different annealing treatments. Further, MA(Sn, Pb)(Br, I)3 thin film was synthesized on the optimized first layer by evaporating MAI and post-annealing. The formed hybrid perovskite thin film exhibited absorptions at 1.0 and 1.7 THz with small absorbance (<10%). Moreover, no chemical and structural defect-incorporated absorption was found. In this study, the possibility of changing terahertz absorption frequency through the mixture of metal cations (Sn+ and Pb+) and halogen anions (Br− and I−) was verified.

ANALISIS KANDUNGAN ENZIM DIASTASE PADA MADU SINGKONG HASIL PROSES VACUUM EVAPORATION DAN VACUUM COOLING

Honey that has a moisture content above 22% should be done moisture reduction process. reduction of water content is done so that honey does not undergo fermentation and has a longer shelf life. One of the ways that can be used to reduce water content in honey is evaporation. Evaporation is of converting some of the water content in the material into steam by utilizing temperatures close to the boiling point of water. However, the minor content of honey, such as the diastase enzyme, is very sensitive to high temperatures. Therefore, vacuum evaporation is used so that the process uses a lower temperature to minimize the damage to the diastase enzyme. The research method was carried out in 3 stages, namely sampling, evaporation process, and sample testing. The results of this study indicate that the process of vacuum evaporation and vacuum cooling can change the proximate content of cassava honey to comply with SNI.