In this study, AlCuMg-B4C nanocomposites reinforced with the B4C particles were produced using the mechanical milling and hot pressing method. The AlCuMg-B4C nanocomposite powders were milled for up to 25 h and then hot pressed in vacuum at 560 degrees C and 300 MPa. The microstructure, density, hardness and tensile strength of the AlCuMg-B4C nanocomposites were investigated as a function of the milling time and the B4C content (wt). The results show that the hot pressed density of the AlCuMg-B4C nanocomposites decreased with increasing B4C content and increasing milling time. The unreinforced AlCuMg alloy showed a high relative density of 992%, which is much higher density than that of the AICuMg-15 wt% B4C nanocomposites produced with a milling time of 25 h. The hardness of the hot pressed nanocomposites was significantly higher than that of the hot pressed nanocomposites produced by using the conventional powder metallurgy. AlCuMg-10 wt% of B4C nano composites produced with milling time of 6 h exhibited the highest tensile strength of 332 MPa. (C) 2016 Elsevier B.V. All rights reserved.