Advanced high-strength and supra-ductile manganese TRIP/TWIP steels with high manganese content (15–25 mass%) and additions of aluminum and silicon (2–4 mass%) were investigated for their mechanical properties under various temperatures (-196 to 400°C) and strain rates (10⁻⁴ to 10³ s⁻¹). These steels exhibit multiple martensitic transformations (γ-fcc → ε-hcp Ms → α-bcc Ms) in TRIP steel, leading to high tensile strength (>1000 MPa) and improved elongation to failure (>50%). The austenitic TWIP steel shows extensive twin formation at low and high strain rates below 150°C, resulting in high tensile ductility (>80%) and energy absorption without brittle fracture. The governing microstructural parameters are the stacking fault energy (Γfcc) of fcc austenite and the Gibbs free energy (ΔGγ→ε) of the martensitic transformation. These parameters are strongly influenced by manganese content and additions of aluminum and silicon. Aluminum increases Γfcc and suppresses the γ-fcc → ε-hcp Ms transformation, while silicon sustains the transformation and decreases Γfcc. At Γfcc ≈ 25 mJ/mol and ΔGγ→ε > 0, the twinning mechanism is favored. At lower Γfcc (<16 mJ/mol) and ΔGγ→ε > 0, martensitic phase transformation dominates. The TRIP steel exhibits pronounced strain hardening with a strain hardening exponent of n=0.8, high tensile strength of ~1100 MPa, and elongation to failure of ~55%. The TWIP steel has a low flow stress of ~280 MPa, moderate tensile strength of ~650 MPa, and high elongation to failure of ~95%, with excellent impact toughness independent of temperature. The mechanical properties of the TRIP and TWIP steels were evaluated under various temperatures and strain rates. The TRIP steel shows high strength and ductility, while the TWIP steel exhibits high elongation and energy absorption. The TRIP steel's deformation behavior is improved by increasing the strain rate to 10⁻¹ s⁻¹, promoting multiple martensitic transformations and enhancing plasticity. The TWIP steel's forming limit exceeds that of austenitic stainless steels. The TWIP steel has high specific energy absorption (0.5 J/mm³) and excellent impact toughness even at high strain rates and low temperatures. These steels have potential applications in the automotive industry, civil engineering, and cryogenic techniques due to their high strength, ductility, and energy absorption capabilities.Advanced high-strength and supra-ductile manganese TRIP/TWIP steels with high manganese content (15–25 mass%) and additions of aluminum and silicon (2–4 mass%) were investigated for their mechanical properties under various temperatures (-196 to 400°C) and strain rates (10⁻⁴ to 10³ s⁻¹). These steels exhibit multiple martensitic transformations (γ-fcc → ε-hcp Ms → α-bcc Ms) in TRIP steel, leading to high tensile strength (>1000 MPa) and improved elongation to failure (>50%). The austenitic TWIP steel shows extensive twin formation at low and high strain rates below 150°C, resulting in high tensile ductility (>80%) and energy absorption without brittle fracture. The governing microstructural parameters are the stacking fault energy (Γfcc) of fcc austenite and the Gibbs free energy (ΔGγ→ε) of the martensitic transformation. These parameters are strongly influenced by manganese content and additions of aluminum and silicon. Aluminum increases Γfcc and suppresses the γ-fcc → ε-hcp Ms transformation, while silicon sustains the transformation and decreases Γfcc. At Γfcc ≈ 25 mJ/mol and ΔGγ→ε > 0, the twinning mechanism is favored. At lower Γfcc (<16 mJ/mol) and ΔGγ→ε > 0, martensitic phase transformation dominates. The TRIP steel exhibits pronounced strain hardening with a strain hardening exponent of n=0.8, high tensile strength of ~1100 MPa, and elongation to failure of ~55%. The TWIP steel has a low flow stress of ~280 MPa, moderate tensile strength of ~650 MPa, and high elongation to failure of ~95%, with excellent impact toughness independent of temperature. The mechanical properties of the TRIP and TWIP steels were evaluated under various temperatures and strain rates. The TRIP steel shows high strength and ductility, while the TWIP steel exhibits high elongation and energy absorption. The TRIP steel's deformation behavior is improved by increasing the strain rate to 10⁻¹ s⁻¹, promoting multiple martensitic transformations and enhancing plasticity. The TWIP steel's forming limit exceeds that of austenitic stainless steels. The TWIP steel has high specific energy absorption (0.5 J/mm³) and excellent impact toughness even at high strain rates and low temperatures. These steels have potential applications in the automotive industry, civil engineering, and cryogenic techniques due to their high strength, ductility, and energy absorption capabilities.