On August 16, 2026, a team from the Institute of Mechanics at Beijing University of Technology (first author Wei Rao, corresponding author Qingsheng Yang, in collaboration with Southwest Jiaotong University and Beijing Institute of Technology) published a paper in the International Journal of Mechanical Sciences (IJMS, CAS Zone 1 Top, Q1) titled "Nonequilibrium thermodynamics perspective for shear localization in additive manufacturing" (DOI: 10.1016/j.ijmecsci.2026.111459). The study utilized TC4 (Ti-6Al-4V) round bars (φ12.5mm × 72mm) fabricated via selective laser melting on an EasyMFG EP-M450H system, followed by stress-relief annealing at 800°C for 2 hours. Monotonic tensile tests were conducted at temperatures ranging from 175°C to 400°C with three build orientations (0°, 45°, 90°), combined with μCT pore characterization and FE-SEM fractography. A constitutive model incorporating local nonequilibrium configuration features, dislocation evolution, and cumulative plastic damage was developed within an irreversible nonequilibrium thermodynamics framework, with finite element predictions showing good agreement with experimental results. Mechanistically, the synergistic effect of pore defects and heterogeneous microstructure triggers multiple localized damage nucleation sites that coalesce to form mature shear bands. Microstructural inhomogeneity plays a dual role—it promotes early shear band nucleation via stress concentration while simultaneously suppressing uncontrolled propagation through dislocation accumulation and work hardening. This work clarifies the physical origins of shear localization in additively manufactured titanium alloys. Value for powder buyers: ① The research confirms that failure in AM titanium alloys is governed by the synergistic effect of porosity and microstructural inhomogeneity. Porosity control of TC4 powder (hollow powder ratio, sphericity, satellite particles) directly impacts the failure risk of fabricated components, and technical procurement agreements should tighten these specifications. ② Aerospace customers are increasingly demanding traceability of batch-to-batch microstructural consistency in titanium powder. Suppliers with validated powder-process combined data will have a competitive advantage in bidding. ③ Looking ahead, defect engineering and gradient microstructure design will redefine next-generation titanium powder specifications. It is recommended to monitor the technology iterations of leading titanium powder manufacturers.