Properties of AA6061 aluminum alloy reinforced with different intermetallics and ceramics particles

Aluminum alloys have been increasingly applied as a structural material in composite materials using metal matrix due to their excellent mechanical properties and low weight. The reinforcement are of fundamental importance in composite materials, owing to the their responsibility to support stresses acting on the metal matrix. Therefore, ceramic reinforcements can be replaced by intermetallic components with high mechanical properties and good thermal stability. The intermetallic components react chemically with the matrix, characterized by strong interactions, which makes possible the development of the new families of materials. The composite materials using aluminum reinforced with nickel aluminides and ceramic were developed using techniques based on a combination of powder metallurgy and extrusion processes, which makes possible to obtain more dense materials under lower processing temperatures. The powders of AA6061 and Ni3Al were manually mixed for 30 minutes, with different percentages of intermetallics and ceramics particles, 5 and 10% in weight. The composite powders were submitted to a hot extrusion process for 40 minutes at 540 degrees C, and 385 MPa, with a reduction ratio of 25:1. This process insures extruded composites with a refined structure and a good distribution of the reinforcement particles. The material characterization were performed through structural analysis via scanning electron microscopy; mechanical behavior via tensile and hardening tests; and analysis of the fracture. The results show that the method used is effective to obtain composite materials with improved characteristics.