Characterization of shock waves treated aluminum nitride powder and its potential for low-temperature sintering

AlN powder is treated by shock waves with pressure of 9.8 GPa. X-ray line broadening effect is found as the result of strain stored in shocked AlN lattice. This resultant average strain is estimated to be 2.85 ×10−3. The related dislocation density in shocked AlN powder is calculated to be in the order of 1011 cm−2. The energy stored in shocked powder is estimated to be 0.36 cal g−1. The low temperature pressureless sintering process of shocked AlN powder with 6 wt.% additives is investigated. The obtained shocked sample sintered at 1610°C for 4 h, has a density of 3.33 g cm−3, while unshocked sample has a poor value of 2.59 g cm−3. This shows that the dislocation in shocked AlN sample can promote the low-temperature sintering. Furthermore, the recover behavior of strain is studied in this paper. The changes of X-ray broadening in the shocked samples after being sintered at different temperatures for different soaking times are examined. The results show that the strain recover effect is strengthened with the increase of sintering temperature and soaking time.