Exploring Strength and Ductility of Non-Equilibrium Microstructures Using Nano- and Micromechanics

Highly heterogenous and non-equilibrium microstructures require rigorous characterization of mechanical performance with good spatial resolution. Although such materials systems are complex, the ability to engineer unique combinations of properties make them of general interest to the materials science community. Here, nano/micromechanics are used to explore microstructure – microchemistry relationships in industrially relevant material systems, including grade 2 titanium welds. Not only is this system heterogeneous, but the rapid cooling gives rise to non-equilibrium microstructures. High throughput nanoindentation is used to determine local mechanical behavior, and the results are correlated with electron backscatter diffraction and energy dispersive spectroscopy data to provide a detailed map of chemistry/structure/performance. Unsupervised machine learning is used to cluster the data, accelerating the analysis of, and correlation between, regions of the material from which each of their statistics can then be extracted. To characterize the local toughness, micro-cantilever beams with accompanying local chemical and structural analysis were also fabricated and tested.