A new process discovered at an Australian research institute could lead to the production of aluminum airplanes that get stronger the longer they are left to “bake” in the sun. Roger Lumley, a scientist with CSIRO Elaborately Transformed Metals (CETM), says if aluminum panels are allowed to cure in the sun instead of in a high-temperature furnace, the metal becomes 20 percent tougher and up to eight times more resistant to rupture on impact. “We have developed two heat treatments using our new knowledge, both of which overcome the age-old problem of either increasing the strength of aluminum and reducing its fracture toughness, or vice versa,” Lumley says. One experimental process reduces the furnace time from six hours to one hour, and the Australian sunshine completes the treatment, Lumley says. “Significantly, it means aluminum car body panels, for example, can be assembled and painted (the baking cycle used to harden the paint adds to the process), and then they will continue to strengthen in the sun. The process would continue, albeit at a slower rate, for the life of the vehicle,” Lumley says. CETM manager Barrie Finnin said the process would be ideal for aircraft skins, where weight reduction and high strength are paramount. The process also saves time and energy over conventional techniques, and in most cases requires no additional equipment. The patented technology is now being tested and evaluated in Australia and Mexico.
