• Optimal energy density (292–333 J/mm³) yields highest material density and impact resistance; exceeding 333 J/mm³ introduces keyhole defects.
• Peak dynamic strength at 292 J/mm³ is 8.4–17.6% higher than at 500 J/mm³, highlighting energy density as a critical process parameter.
• At strain rates ≥2000 s⁻¹, failure occurs rapidly (crack initiation within 12 μs, strength limit at ~110 μs), while lower rates produce only microcracks and adiabatic shear bands.
• Fracture morphology transitions from ductile to brittle with increasing strain rate, informing design for high-impact applications.