Microgravity effects on microstructure and mechanical properties of ESL solidified Ti70.5Fe29.5 eutectic alloy
Year: 2026
Type: article
Abstract: : Ti 70.5 Fe 29.5 eutectic alloy has emerged as a promising candidate for aerospace applications, owing to its low density (∼5.6 g/cm 3 ), high strength (≥ 2.2 GPa), and cost-effectiveness. In this study, the solidification behavior and mechanical properties of Ti 70.5 Fe 29.5 eutectic alloy were investigated under various undercoolings ( ) using the electrostatic levitation technique (ESL) on the ground and aboard the China Space Station (CSS). A comparable range of 18-134 K was achieved under two conditions. The crystal growth velocity ( ) attained 435 mm⋅s -1 in this case. Increasing induced the evolution of eutectic morphology from lamellar to fine granular, with the anomalous eutectic fraction peaking at 88%. Furthermore, the Ti 2 Fe phase emerged within 57-108 K on the ground and 18-114 K in space. The wider ΔT range achieved in space stemmed from surface tension-driven Marangoni convection which dominated melt flow in microgravity. Meanwhile, a single crystal was formed under 57-134 K in both environments. Importantly, the alloy undercooled at 114 K in space exhibited the highest mechanical properties, featuring a nano-hardness of 10.30 GPa and Vickers hardness of 554 HV, which exceeded other space-undercooled, ground-undercooled and as-cast counterparts. Enhanced hardness originated from ultrahard Ti 2 Fe (21% above TiFe, 40% above β-Ti), refined eutectic spacing ( ), high-volume-fraction anomalous eutectic and Fe solute solid-solution strengthening in the β-Ti matrix. The space-130 K specimen shows the highest plastic displacement ratio of 0.722, which arises from its single-crystal microstructure with suppressed hard Ti 2 Fe precipitation. The findings of this work contribute to further understanding of novel microstructure formation and the property evolution of eutectic alloys.
Authors: Yongxia Fan, Ying Ruan, Qingbo Ao, Jianzhong Wang
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,640
OpenAlex ID: W7225399977