The carbides, tensile properties, and work-hardening behavior of annealed H13 die steels with varied yttrium contents

In this study, the micro-alloying of rare-earth yttrium (Y) was employed to improve the fracture behavior and work-hardening ability of H13 die steel. The improved work-hardening ability was attributed to modification of Cr23C6 and VC carbides by the addition of Y. The strip-typed Cr23C6 carbides originally distributed along the grain boundary were interrupted and tended to sphemidize with increasing Y content. Compared with 0Y-H13 steel, the quantity of spherical VC carbides significantly increased in 0.013Y-H13 steel. A higher-density dislocations and intensive interaction between precipitates and dislocation led to a higher work-hardening exponent. Additionally, fractographic studies revealed that the fracture mode transition from cleavage failure to ductile rupture with increasing Y content. Moreover, excess Y content (0.044%) resulted in the appearance of inclusion clusters in dimples, which were detrimental to fracture and work-hardening behavior.

Automated summary

In this study, the micro-alloying of rare-earth yttrium (Y) was used to improve the fracture behavior and work-hardening ability of H13 die steel by modifying Cr23C6 and VC carbides. The addition of Y led to interruption and sphericalization of Cr23C6 carbides, increased quantity of VC carbides, and higher work-hardening exponent. Fractographic studies showed a transition from cleavage failure to ductile rupture with increasing Y content, but excess Y content resulted in detrimental inclusion clusters in dimples.