TY - JOUR

T1 - Explanation for the linear solid/liquid interface recoil observed during directional solidification of a TRIS-NPG alloy under microgravity conditions

AU - Ludwig, Andreas

AU - Mogeritsch, Johann Peter

AU - Barati, Hadi

AU - Wu, Menghuai

AU - Kharicha, Abdellah

PY - 2024/7/23

Y1 - 2024/7/23

N2 - During the initial transient stage of a directional alloy solidification experiment, a solid/liquid interface asymptotically recoils from a position that is given by the liquidus temperature to a position given by the solidus temperature. Recent observations onboard the International Space Station revealed that for the organic compound TRIS-NPG, the recoil appears much larger and varies linearly with time. In addition, such conditions were found that the high-temperature non-facetted plastic phase gradually dissolves and, although it seems contradictory to the interpretation of the thermodynamics of the binary system, the low-temperature facetted phase comes into direct contact with the liquid. Both unexpected observations can be understood by assuming that the TRIS-NPG alloy gradually decomposes at the hot side of the furnace. The decomposition products are then transported to the solid/liquid interface by diffusion and the sample motion. The presence of decomposition products changes the binary alloy into a TRIS-NPG-X ternary alloy, with a liquidus temperature that decreases with an increasing amount of decomposed substances.

AB - During the initial transient stage of a directional alloy solidification experiment, a solid/liquid interface asymptotically recoils from a position that is given by the liquidus temperature to a position given by the solidus temperature. Recent observations onboard the International Space Station revealed that for the organic compound TRIS-NPG, the recoil appears much larger and varies linearly with time. In addition, such conditions were found that the high-temperature non-facetted plastic phase gradually dissolves and, although it seems contradictory to the interpretation of the thermodynamics of the binary system, the low-temperature facetted phase comes into direct contact with the liquid. Both unexpected observations can be understood by assuming that the TRIS-NPG alloy gradually decomposes at the hot side of the furnace. The decomposition products are then transported to the solid/liquid interface by diffusion and the sample motion. The presence of decomposition products changes the binary alloy into a TRIS-NPG-X ternary alloy, with a liquidus temperature that decreases with an increasing amount of decomposed substances.

U2 - 10.1016/j.jcrysgro.2024.127824

DO - 10.1016/j.jcrysgro.2024.127824

M3 - Article

VL - 644.2024

JO - Journal of crystal growth

JF - Journal of crystal growth

SN - 0022-0248

IS - 15 October

M1 - 127824

ER -