In this study, Al/15 wt.% BN nanocomposite was fabricated by high energy ball milling, cold compaction, and sintering process. Then the effect of milling process on the morphology change and phase evaluation was studied. The Aluminum (45 mu m) and hexagonal boron nitride (70 nm) powders were milled using planetary ball mill under a pure argon atmosphere for various times of 75, 150, 300 and 600 min. The as-milled powders were consolidated at 400 MPa pressure and sintered at 600 degrees C for 60 min. The morphology change evaluation studied by using scanning electron microscopy (SEM) showed that the equiaxed composite powders were obtained after a short time milling process of 150 min. The steady state condition between welding and fracturing occurred by continuous milling up to 600 min. The results of X-ray diffraction patterns and differential scanning calorimetric (DSC) revealed that the BN particles completely decomposed to boron and nitrogen and dissolved in the Al matrix after 300 min of ball milling and the AIN and AIB(2) as in-situ phases were formed after sintering at temperatures above 580 degrees C. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.