We studied the performance of fine-tuning open-source LLMs for a range of different chemical questions. We benchmark their performances against “traditional” machine learning models and find that, in most cases, the fine-tuning approach is superior.

The solidification sequence of an AlMg4.7Si8 alloy is imaged in situ by synchrotron microtomography. Tomograms with (1.4 μm)3/voxel have been recorded every minute while cooling the melt from 600 °C at a cooling rate of 5 K min−1 to 540 °C in the solid state. The solidification process starts with the three-dimensional evolution of the α-Al dendritic structure at 590 °C. The growth of the α-Al dendrites is described by curvature parameters that represent the coarsening quantitatively, and ends in droplet-like shapes of the secondary dendrite arms at 577 °C. There, the eutectic valley of α-Al/Mg2Si is reached, forming initially octahedral Mg2Si particles preferentially at the bases of the secondary dendrite arms. The eutectic grows with seaweed-like Mg2Si structures, with increasing connectivity. During this solidification stage Fe-aluminides form and expand as thin objects within the interdendritic liquid. Finally, the remaining liquid freezes as ternary α-Al/Mg2Si/Si eutectic at 558 °C, increasing further the connectivity of the intermetallic phases. The frozen alloy consists of four phases exhibiting morphologies characteristic of their mode of solidification: α-Al dendrites, eutectic α-Al/Mg2Si “Chinese script” with Fe-aluminides, and interpenetrating α-Al/Mg2Si/Si ternary eutectic.

The evolution of the microstructure of an AlMg4.7Si8 alloy is investigated by scanning electron microscopy and ex situ synchrotron tomography in as-cast condition and subsequent solution treatments for 1 h and 25 h at 540 °C, respectively. The eutectic Mg2Si phase, which presents a highly interconnected structure in the as-cast condition, undergoes significant morphological changes during the solution heat treatment. Statistical analyses of the particle distribution, the sphericity, the mean curvatures and Gaussian curvatures describe the disintegration of the interconnected seaweed-like structure followed by the rounding of the disintegrated fractions of the eutectic branches quantitatively. The ternary eutectic Si resulting from the Si-surplus to the stoichiometric Mg2Si ratio of the alloy undergoes similar changes. The morphological evolution during solution heat treatment is correlated with results of elevated temperature compression tests at 300 °C. The elevated temperature compressive strength is more sensitive to the degree of interconnectivity of the three dimensional Mg2Si network than to the shape of the individual particles.

► The internal architecture of strip cast AlMg7.3Si3.5 was investigated by tomography. ► Magnified synchrotron tomography was utilised to reveal the different phases. ► The effect of solution heat treatment on the microstructure was quantified. ► The eutectic Mg2Si spheroidises and partially looses its interconnectivity. ► The decrease in high temperature strength is correlated to the tomographic results.