Robert C Albers

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We propose a new direct mechanism for the pressure driven ! ! martensitic transformation in pure titanium. A systematic algorithm enumerates all possible pathways whose energy barriers are evaluated. A new, homogeneous pathway emerges with a barrier at least 4 times lower than other pathways. The pathway is shown to be favorable in any nucleation model.(More)
I mpurities control phase stability and phase transformations in natural and man-made materials, from shape-memory alloys 1 to steel 2 to planetary cores 3. Experiments and empirical databases are still central to tuning the impurity eff ects. What is missing is a broad theoretical underpinning. Consider, for example, the titanium martensitic(More)
Martensitic phase transitions appear in a diverse range of natural and engineering material systems. Examination of the energetics and kinetics of the transformation requires an understanding of the atomic mechanism for the transformation. A systematic pathway generation and sorting algorithm is presented and applied to the problem of the titanium ␣ to ␻(More)
Equilibrium free energies for the ␣ and ␻ phases of Ti are constructed. The result is a consistent picture of the ambient pressure, static high pressure, and shock data, as well as first-principles electronic structure calculations. The Hugoniot consists of three segments: a metastable ␣-phase region, a transition region, and an ␻-phase branch. All the(More)
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