Achieving exceptional Strength-Ductility at 4.2 K in High-Manganese Steels: The influence of pre-strain and aging on Manipulating microstructure and deformation behavior

• Pre-strain and aging (PA) treatment significantly enhances yield strength (∼165 MPa) in 5Al steel via Taylor lattice and dislocation strengthening, with retained high ductility (34.2%). • Al (5 wt%) effectively suppresses detrimental (Fe, Mn) 23 C 6 carbide precipitation during pre-strain & aging, preventing embrittlement. • The 5Al-PA steel achieves an outstanding balance of high strength and high ductility at 4.2 K, demonstrating superior resistance to PA-induced embrittlement. • At 4.2 K, PA-induced microstructure stability enables superior strength-ductility synergy through microband/twinning-induced plasticity, rivaling the best-performing cryogenic alloys.