Fig. 1. SEM morphology and particle size distribution of AM40 die steel powder. (a) Powder morphology; (b) particle size distribution

Fig. 2. Schematics of AM40/H13 bimetallic structure. (a) Die steel; (b) test rod

Fig. 3. Shape and size of AM40/H13 bimetal die steel tensile specimen

Fig. 4. Microstructure morphologies of AM40 samples. (a) Optical morphology of as-deposited AM40; (b) SEM morphology of as-deposited AM40; (c) optical morphology of heat treated AM40; (d) SEM morphology of heat treated AM40

Fig. 5. Microstructure morphologies of H13 samples. (a) Optical morphology of annealed H13; (b) SEM morphology of annealed H13; (c) optical morphology of heat treated H13; (d) SEM morphology of heat treated H13

Fig. 6. X-ray diffraction patterns of AM40 and H13. (a) AM40; (b) H13

Fig. 7. Microstructure morphologies of AM40/H13 bimetallic structure interface. (a)(b) As-deposited; (c)(d) heat treated

Fig. 8. Weld pool morphologies of AM40/H13 bimetal structural interface. (a)‒(c) As-deposited; (d)‒(f) heat treated

Fig. 9. Alloy element distributions of AM40/H13 bimetallic structural at interface before and after heat treatment. (a) Cr; (b) V; (c) Mo

Fig. 10. EBSD analysis of interface region of AM40/H13 bimetallic structure. (a) As-deposited, IPF; (b) as-deposited, LAM; (c) as-deposited, HAGB/LAGB; (d) heat treated, IPF; (e) heat treated, LAM; (f) heat treated, HAGB/LAGB

Fig. 11. Microhardness of AM40/H13 bimetallic structure at interface

Fig. 12. Tensile stress-strain curves

Fig. 13. Tensile longitudinal fracture morphologies. (a) As- deposited AM40/H13; (b) HT AM40/H13; (c) HT AM40; (d) HT H13

Fig. 14. Tensile transverse fracture morphologies. (a)(c) As-deposited AM40/H13; (b)(d) HT AM40/H13; (e) HT AM40; (f) HT H13