The coating of ex–situ AlN particles with in–situ AlN nanolayers in an (AlN + AlB2)/Al composite

•An (AlN + AlB2) /Al composite reinforced with both ex–situ and in–situ AlN was prepared.•The ex–situ AlN particles were coated by in–situ AlN nanolayers.•The ultimate tensile strength of the composite can be 416 MPa at 25 °C and 242 MPa at 350 °C.