Dense bulk alumina (Al2O3) has been prepared by explosive compaction and its microstructure has been investigated by optical microscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The average microhardness of the alumina compact is about 171 HV0.025. Ultra-thin alumina films with glassy (translucent) appearance formed during the explosive compaction process. Nanograin Al2O3 particles are covered by amorphous Al2O3 which help to achieve a dense microstructure by promoting interparticles bonding. Phase transformation from γ-Al2O3 to α-Al2O3 during the explosive compaction process has been confirmed. Formation of the alumina compact is due to the large cooling rate and the high pressure during the explosive compaction.

Ultrafine-grained (UFG) high purity aluminum exhibits a variety of attractive mechanical properties and special deformation behavior. Equal channel angular pressing (ECAP) process can be used to easily and effectively refine metals. The microstructure and microtexture evolutions and grain boundary characteristics of the high purity aluminum (99.998%) processed by ECAP at room temperature are investigated by means of TEM and EBSD. The results indicate that the shear deformation resistance increases with repeated EACP passes, and equiaxed grains with an average size of 0.9 μm in diameter are formed after five passes. Although the orientations distribution of grains tends to evolve toward random orientations, and microtextures (80°, 35°, 0°), (40°, 75°, 45°) and (0°, 85°, 45°) peak in the sample after five passes. The grain boundaries in UFG aluminum are high-angle geometrically necessary boundaries. It is suggested that the continuous dynamic recrystallization is responsible for the formation of ultrafine grains in high purity aluminum. Microstructure evolution in the high purity aluminum during ECAP is proposed.

The microstructure of AISI201 stainless steel deformed in the first compression cycle of MAC at 973 K in air was investigated. It is suggested that the continuous dynamic recrystallization (cDRX) and dynamic recovery are responsible for the formation of strain-induced fine austenitic grains.

Local melting zone encountered in sections of the cladding interface is a distinguished phenomenon of the explosive cladding technique. The thickness and morphology of the melting zone in the Ti/NiCr explosive cladding bar are investigated by means of optical microscopy. Results show that the distribution of the melting zone in the interface of the Ti/NiCr explosive cladding bar is uniform and axisymmetric, and boundaries of the melting zone are circular arcs, whose center points to the center of the NiCr bar. The bamboo-shaped cracks generate in the melting zone. The thickness of the melting zone decreases with reducing of the stand-off distance and the thickness of the explosive. A physical model of the melting zone in the interface of the explosive cladding bar is proposed.