Purdue Research Boosts Aluminum Strength, Ductility
Feb. 15, 2018—Purdue announced last month researchers have developed a means of changing aluminum’s microstructure to boost ductility and produce strength equivalent to stainless steel, and the alloys might have ramifications on collision repair someday.
“Most lightweight aluminum alloys are soft and have inherently low mechanical strength, which hinders more widespread industrial application,” Purdue School of Materials Engineering Professor Xinghang Zhang said in a statement. “However, high-strength, lightweight aluminum alloys with strength comparable to stainless steels would revolutionize the automobile and aerospace industries.”
If brought to market, that could make aluminum closures even more attractive than they’re already expected to be for OEMs over the next decade.
The crystal lattice of a metal involves repeating atomic layers; scientists call absent layers “stacking faults” and dual layers of stacking faults “twin boundaries,” according to Purdue. While copper and silver are receptive to stacking faults, aluminum’s higher stacking fault energy make it harder to artificially induce them.
“It has been shown that twin boundaries are difficult to be introduced into aluminum. The formation of the 9R phase (a type of stacking fault) in aluminum is even more difficult because of its high stacking fault energy,” Zhang said in a statement. “You want to introduce both nanotwins and 9R phase in nanograined aluminum to increase strength and ductility and improve thermal stability.”
The team figured out how to do both.
“These results show how to fabricate aluminum alloys that are comparable to, or even stronger than, stainless steels,” Zhang said in a statement. “There is a lot of potential commercial impact in this finding.”