High strength Aluminium matrix composites reinforced with nanoparticulate materialsWednesday (08.11.2017) 16:40 - 17:00 Part of:
Aluminium alloys are reinforced with different nanoparticulate materials using a simple powder metallurgy approach. Both micro-scale matrix powder and nanopowders are mixed in a high energy ball mill and then hot pressed. For high reinforcement contents, the hardness of the composites increases up to 7-8 times while the ultimate tensile strength increases by a factor of 4. However, the ductility is inversely dramatically low, below 1%.
An optimization of the processing conditions allows reaching high strength and high elongation at rupture. For instance, a novel planetary ball cube-mill proved to be three times more efficient than conventional ball mills. The hot pressing cycle is also adapted including a degassing/annealing step. Thus the UTS and elongation at rupture of AlMg5 reinforced with nano-alumina particles could be tailored linearly between [560 MPa - 4%] to [400 MPa - 20 %] depending on the nanoparticles content. No further treatment is necessary for achieving these high strength-ductility values. Other processing routes like forging, HIP and Spark Plasma Sintering are shortly compared. Finally the weldability of these composites is demonstrated.