Commercial Processing of Nano Particle Reinforced Aluminum Composites

Gamma Technology has developed and patented a process to introduce nano size alumina particles into aluminum alloys. This process has been scaled from a laboratory process to a prototype process and will be scaled to 300 mm diameter billets that have been extruded into rods and plates. This process does not require expensive procedures and will deliver nano particle reinforced aluminum at a reasonable cost. This paper describes the tensile data for material made during the laboratory and prototype development to demonstrate the successful scale-up of mechanical properties.

The primary matrix alloy is 1100 aluminum. The addition of nanometer size particles add strength and do not compete with precipitates for strengthening the matrix alloy. All testing was conducted using fully annealed samples, 500°C for at least 1 hour followed by furnace cooling to 150°C. The nanometer particles increase the strength of the matrix alloy at room temperature and at elevated temperatures because the nanometer alumina particles are stable at all temperatures and do not dissolve as do precipitates in other aluminum alloys. The elastic modulus of all samples was determined by ultrasonic velocity measurements at room temperature.

The room temperature tensile strength for the 1100 matrix composite went from 90 MPa for the unreinforced matrix to 240 MPa for 3% nano particle composite and 300 MPa for 10% nano particle composite. The tensile elongation for the 1100 matrix went from 40 percent for the unreinforced to 20 percent for the 3 percent composite and 7.5% for the 10% composite. The elastic modulus values of the samples follow the predictions from Halpin and Tsai, AFML TR 67-423 for short fiber reinforced composites.

This talk will detail this work as well as investigations into mixing nano and micron size particles to generate composites with both high modulus and high strength.