Kinetic Diffusion Couple for Mapping Microstructural and Mechanical Data on Ti⁻Al⁻Mo Titanium Alloys

We introduce a new strategy that extends the established diffusion couple approach for efficient mapping of microstructural and mechanical properties in bulk samples. The featured diffusion couples undergo an interdiffusion annealing followed by a thermal/mechanical treatment for creating a blended spectrum of phases and microstructures in the well-grooved continuous composition gradients, which is then further accessible to local high spatially resolving microanalysis probing. The strategy is demonstrated on two diffusion couples, Ti/Ti-7.58Al-4.97Mo and Ti-5.04Al/Ti-1.52Mo, by surveying the spectrums of microstructural and mechanical characteristics created through an appreciation of the β-to-α phase transformation with such microanalysis techniques as electron probe microanalysis, electron backscatter diffraction analysis, and nanoindentation. The examined microstructural characteristics and mechanical properties reveal the variation of phase, morphology, and microhardness based on the changes of the compositions of the overall alloys and the individual phases in these near-β Ti alloys.