Achieving efficient damping performance tuning in NiTi alloy via laser powder bed fusion

NiTi alloys exhibit an impressive damping effect at the damping peak temperature (T_p), and aligning T_p with target temperatures presents significant application value. Traditionally, tuning the damping performance of NiTi alloys demands precise modifications to raw material composition and complex thermomechanical processing. This study achieved an efficient tuning of T_p across a broad 93 K range via laser powder bed fusion (LPBF), eliminating the need for material modifications and complex treatments. Comprehensive experiments and simulations were conducted to reveal the mechanism. Adjusting the laser scanning speed during LPBF modulated the laser–powder interaction, resulting in variations in temperature, lifespan, and volume of the molten pool. These variations facilitated the manipulation of Ni evaporation, enabling the regulation of Ni content and, thus, the tuning of T_p. Notably, a 0.1 at. % increase in Ni content resulted in a 7.55 K decrease in T_p. Despite the efficient tuning of T_p, the damping peak intensity remained high (0.06–0.11), indicating the preservation of the desired damping effect. Additionally, this study discusses the composition and influencing factors of damping peaks in LPBF NiTi alloys. Furthermore, high-damping, lightweight NiTi porous structures were fabricated by LPBF, highlighting the unique advantages over conventional routines. Overall, this study provides new insights and a framework for the efficient tuning of damping performance in NiTi alloys, paving the way for advanced applications of high-damping materials.