Effect of Ultralow‐Temperature Extreme Service Conditions on the Plasticity of TA15 Titanium Alloy for Aeronautics

This study explores the effects of cryogenic treatment on the plasticity of TA15 aerospace titanium alloy under ultralow‐temperature extreme conditions. As a critical engineering material, TA15 titanium alloy finds widespread applications in aerospace and related fields. Given its mechanical properties’ strong dependence on microstructure, this research utilizes laser‐directed energy deposition technology to fabricate TA15 titanium alloy and investigates the use of cryogenic treatment to enhance its microstructure and mechanical performance. Comparative analyses are conducted between as‐built (untreated) samples and those subjected to ultralow temperature treatment. The study evaluates the influence of cryogenic treatment on the alloy's microstructure and mechanical behavior through tensile tests, impact tests, friction‐wear tests, and characterization techniques such as scanning electron microscopy, X‐ray diffraction, and electron backscatter diffraction. Results reveal that cryogenic treatment significantly improves the plasticity of TA15 titanium alloy, increasing fracture engineering strain by ≈17.8% while inducing a minor reduction in ultimate tensile strength and yield strength. This enhancement is attributed to a reduced concentration of β‐stabilizing elements (Mo and V) in the β phase, leading to improved plasticity.