Abstract: The microst ructures at the interfaces of the aluminum matrix composite reinforced by Al₂O₃ particles
were characterized by means of high resolution t ransmission elect ron microscopy (HRTEM). It was revealed that Al(200) and Al (111) planes of the Al matrix should first grow along the surfaces of the Al₂O₃ particles, such orien2tation relationship as Al (200) ∥ Al₂O₃(101 2) and Al [ 011 ] ∥ Al₂O₃ [ 0221 ], and partial-coherent interface exist in one of the interfaces between the Al matrix and the Al₂O₃ particles, a coherent relationship with Al(111) ∥ Al₂O₃  (1120) appears in another interface, but no resultant production is found along those interfaces. Frank partial edge dislocation with 1/ 3 [111 ] Burgers vector, which is responsible for forming of remarkable lat tice deformation field with the scale about 20～30 atomic planes, is observed within the Al mat rix near the interface, however, no dislocations and other defect s are found within the area of the  Al₂O₃ particles near the interfaces. At the same time, the mechanism for forming the interface features is analyzed from the viewpoint of crystallography.