ScholarWorks@경상국립대학교

초록

Despite exceptional mechanical properties demonstrated in laboratory studies, nanostructured steels account for only 0.05% of global steel production. This comprehensive review systematically examines the fundamental barriers preventing technology transfer from laboratory to industrial implementation through an integrated analysis of processing economics, microstructural stability, and technology readiness levels. A comprehensive literature review spanning 2008-2024 analyzes nanostructured steels across severe plastic deformation techniques—equal-channel angular pressing, high-pressure torsion, and accumulative roll bonding alongside thermomechanical processing and additive manufacturing. Severe plastic deformation techniques achieve remarkable grain refinement (20-500 nm) with yield strengths of 800-2500 MPa, representing a median 2.6 × improvement over conventional steels. However, prohibitive barriers emerge: energy consumption of 12-65 kWh/kg versus 1.8-2.2 kWh/kg for conventional processing, cost premiums of 200-592%, and throughput limitations below 1 kg/h. Technology readiness assessments place most severe plastic deformation at laboratory scale versus commercially mature thermomechanical processing. Critical limitations include 60-75% strength loss at 500 °C and inverse strength-toughness correlation with fracture toughness decreasing from 120 to 150 to 40-60 MPa√m as yield strength increases. Emerging heterostructured architectures featuring engineered grain size distributions transcend traditional trade-offs, achieving 800-1200 MPa yield strength while retaining 80-120 MPa√m fracture toughness through three synergistic mechanisms: strain partitioning, back-stress hardening (100-300 MPa), and geometrically necessary dislocation accumulation. Performance index analysis demonstrates 2 × advantage over uniform severe plastic deformation materials. Near-term viable pathways include accumulative roll bonding (2028-2030 timeline), additive manufacturing of 316L stainless steel (current commercialization), and heterostructured architectures (projected 2030-2033 deployment). Three critical research priorities emerge: continuous processing development enabling sustained production exceeding 100 kg/h, microstructural stabilization extending service temperature from 250-300 °C to 300-400 °C, and standardized characterization protocols for structural certification. Success requires substantial coordinated investment across government agencies, industry consortia, and academic partnerships to achieve 0.5-1% global market penetration by 2035.

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