The effect of Al-BN Powder Preparation Method on Tensile Properties of Extruded bulk Nanocomposite

In this study, the Al-BN nanocomposite powders were prepared using two different methods of i) ultrasonic mixing, and ii) planetary ball milling. The Al-BN bulk nanocomposite samples were fabricated by hot extrusion. Morphology of powders through the preparation process and fracture surface were characterized using scanning electron microscopy and the microstructure of optimized bulk nanocomposite sample was investigated by a transmission electron microscopy and electron back scattered diffraction technique (EBSD). The mechanical properties of composite samples were examined by uniaxial tension test. With the use of planetary high energy ball milling and hot extrusion, the ultimate tensile strength of fabricated milled and unmilled pure Al samples reached to 104 MPa and 212 MPa, respectively. The ultimate tensile strength of extruded milled nanocomposite increased to 297, 330, 333MPa by adding 1, 2 and 4 wt. % BN, respectively. In the process of composite powders mixing and hot extrusion, the mechanical properties of samples were significantly decreased. By increasing the BN content within range of 0-6 wt. %, the tensile strength of mixing and extruded composite samples was not changed. On the other hand, the ductility is reduced from 24 % for pure Al to 5 % for Al-6 wt. % BN.