Deformation characteristics of Ti-Ni-Fe based multiphase intermetallic: Experiments and atomistic simulation

• Published in: Journal of alloys and compounds 2025-01, Vol.1010, p.177402, Article 177402
• Main Authors: Panda, Subha S., Sahni, Sandeep, Jayabalan, Bhagyaraj, Subhakar, M., Mukherjee, Subrata, Jain, Jayant, Singh, Sudhanshu S.
• Format: Article
• Language: English
• Subjects: Intermetallic; MD simulation; Superpartials; Yield strength anomaly
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2024.177402

This study deals with the development of Ti-Ni-Fe based multi-phase intermetallic having high strength with enhanced ductility and elucidation of their deformation characteristics. The intermetallic exhibited a compressive strain and strength of ⁓ 11 % and ⁓ 2.1± 0.112 GPa at room temperature (RT), respectively. MD simulation at RT showed a higher dislocation density in the DO24 phase, where most of the dislocations were found to be superpartials 13101̅0 and 1311̅00 separated by super intrinsic stacking faults (SISF), which was further corroborated with TEM analysis. It was found that despite its low volume fraction, DO24 phase governed the plastic deformation. Further, hot compression of Ti45Ni50Fe5 exhibited yield strength anomaly (YSA), where yield strength decreased from room temperature to 373 K followed by an increase at 473 K and 573 K. MD simulation of hot compression showed lower dislocation density (⁓300–551×10−6Å−2) for B2 matrix at all temperatures, indicating strength is predominantly governed by it. The dislocation density of B2 matrix was found to increase with temperature up to 373 K followed by a decrease at 473 K and 573 K. This difference in dislocation density has been attributed to the cross-slip of 121̅11 screw partials from {110} plane to {211} plane, resulting in the formation of dislocation lock that led to YSA behavior. •Ti-Ni-Fe multiphase intermetallic exhibited a maximum compressive strain and strength of ⁓ 11 % and 2.1 ± 0.112 GPa respectively, at RT.•Fe substituted Ni3Ti phase governed the plastic deformation at room and elevated temperatures.•Multiphase intermetallic exhibited yield strength anomaly at the temperature range of 473 – 573 K.•½ 111 screw partials in B2 phase are responsible for the yield anomaly of multiphase intermetallic.