Blacksburg, VA--The high speed aircraft of the future will be made of advanced materials such as titanium, adhesively bonded to form efficient lightweight structures. Before such craft go into general production, however, "a potential problem with the bonds degrading at elevated temperature will have to be solved," explains John G. Dillard, professor of chemistry at Virginia Tech.
Dillard and Rajesh Tiwari, a graduate student, investigated the durability of bonded titanium - aluminum alloy (Ti-6Al-4V) using a polymeric adhesive. They discovered that the process used to prepare the surface of the alloy for the adhesive contributes to the degradation. Anodization, or an electrolytic bath to introduce oxide and enhance molecular attachment, is used to prepare the surface.
"We've observed that at high temperatures over time, the adhesive bonds fail. It appears that failure is a result of aluminum forming aluminum fluoride from a reaction of fluoride that is left in the oxide during the anodization process. The formation of aluminum fluoride weakens the bond."
Dillard will present the research at the 218th American Chemical Society National Meeting in New Orleans. "Durability of Adhesively Bonded Ti-6Al-4V" (PMSE paper 129) will be presented Tuesday, Aug. 24, at 3:55 p.m. in the Hilton Riverside Magnolia Room.
Contact for further informaton: John Dillard, 540-231-6926 or dillardj@vt.edu . He will be out of the office Aug. 20-30.