Fig. 1. Mn13 steel plate, experimental setup and schematic diagram. (a) Microstructure and composition of Mn13 steel plate; (b) laser remelting device and principle; (c) ultrasonic rolling strengthening device and principle

Fig. 2. Cross-sectional microstructures and composition undercooling principle of laser remelted high manganese steel. (a) Low magnification SEM photo of cross-sectional microstructure from top to substrate; (b) top microstructure; (c) middle microstructure; (d) bottom microstructure; (e) schematic of constitutional undercooling in molten pool

Fig. 3. Microhardness measurement plan and results of laser remelted high manganese steel before and after ultrasonic rolling. (a) Measurement plan; (b) microhardness distribution

Fig. 4. Wear results of laser remelted high manganese steel before and after ultrasonic rolling. (a) 2D contour of worn surface; (b) volume wear rate; (c) surface 3D contour without ultrasonic rolling; surface 3D contours under ultrasonic rolling with static pressure of (d) 100 N and (e) 200 N

Fig. 5. Wear surface morphologies of laser remelted high manganese steel before and after ultrasonic rolling. (a)(b) Without ultrasonic rolling; (c)(d) under ultrasonic rolling with static pressure of 100 N; (e)(f) under ultrasonic rolling with static pressure of 200 N

Fig. 6. Composition segregation and solidification principle of laser remelted high manganese steel. (a) EBSD reverse pole diagram; (b) EPMA backscatter map; (c)‒(e) distributions of Mn and Fe elements; (f) solidification principle of paste zone; (g) element segregation between dendrites under finite diffusion condition

Fig. 7. Cross-sectional microstructures of laser remelted high manganese steel before and after ultrasonic rolling. (a)(b) Without ultrasonic rolling; (c)(d) under ultrasonic rolling with static pressure of 100 N; (e)(f) under ultrasonic rolling with static pressure of 200 N

Fig. 8. Surface micro-morphologies of laser remelted high manganese steel before and after ultrasonic rolling. (a)(b) Without ultrasonic rolling; (c)(d) under ultrasonic rolling with static pressure of 100 N; (e)(f) under ultrasonic rolling with static pressure of 200 N