Improving the dynamic mechanical properties of high-carbon and high-manganese steel via laser wire additive manufacturing

<p indent="0mm">The low yield strength and hardness of high-carbon and high-manganese steel before deformation limit its wide application under impact load conditions. In order to improve the dynamic mechanical properties of high-carbon and high-manganese steel under impact load and extend its service life, laser wire additive manufacturing technology was adopted to strengthen the high-carbon and high-manganese steel. This study used laser wire additive manufacturing technology to prepare high-carbon and high-manganese steel samples on a cast high-manganese steel substrate. The mechanical properties of a separated Hopkinson pressure bar under impact loading were quantitatively studied, and the microstructure before and after the dynamic compression process was analyzed using characterization methods such as optical microscopy, scanning electron microscopy, electron probe X-ray microscopy, electron backscatter diffraction, and transmission electron microscopy to reveal the deformation and strengthening mechanisms. The results showed that the yield strength of high-carbon and high-manganese steel prepared via laser wire additive manufacturing technology under impact load reached <sc>(764±10) MPa,</sc> the hardness increased from (314±7) to <sc>(619±22) HV_0.3,</sc> and the work hardening index was 0.88, all higher than those of cast high-manganese steel. Among these, the high yield strength is attributed to the strengthening of grain boundaries and dislocations caused by heterogeneous microstructures, accounting for 60%. The generation of dislocation networks, stack fault networks, and nanotwins during dynamic compression maintains excellent work hardening ability. The use of laser wire additive manufacturing technology to prepare high-carbon and high-manganese steel and study its mechanical properties and microstructure evolution under impact load provides a new method for high-performance repair and remanufacturing of large high-manganese steel components in mining machinery, which is crucial.