Cyberalloys – TRIP Titanium by design
Participants: Prof. Gregory B. Olson
Titanium alloys have many excellent properties, such as low density, high strength, high fracture toughness, good corrosion resistance, and weldability, which make them ideal candidates as naval structural materials. This project, funded by Office of Naval Research, is aimed to design a new near-α Titanium alloy for naval structural applications with both the high strength of Ti-64 and the high fracture toughness of Ti-5111. In order to enhance strength and fracture toughness simultaneously, transformation-induced plasticity (TRIP) effect was used. A new generation of TRIP toughened near-α Ti alloy Ti-8111Fe, meeting predicted strength (120ksi) with required phase stability and transformation dilatancy, was computationally designed. Mechanistic models on the thermodynamics and kinetics of martensitic transformation in titanium alloys were built and applied to calculate the characteristic MSσ temperatures defining the β phase stability at the stress states of uniaxial tension (ut) and crack tip (ct). Martensitic transformation dilatation was calculated from room temperature molar volume database developed for β, α’and α” phases. The model predictions of transformation kinetics, transformation dilatancy and associated toughening behavior is being experimentally tested.
See more information at our group website: http://srg.northwestern.edu/