Laser powder bed fusion of bimetallic stainless steel/Nickel-based superalloy: Interface and mechanical properties

Potential applications of steel/nickel bimetals in corrosive environments are of increasing interest. In this study, bimetallic 316L/Hastelloy X was processed via laser powder bed fusion (L-PBF) using different parameters. Results indicated that the rapid cooling of L-PBF reduced the element segregation and carbide formation, thus leading to an interface free of cracks. However, also due to rapid solidification, the constituent elements of dissimilar materials at the interface were not mixed properly. With the increasing laser energy density, the interfacial width increased from dozens to hundreds of microns. The epitaxial grain growth from 316L to Has-telloy X was observed under the optimal processing parameters. The microhardness first declined at the front of the 316L side and then continuously increased in the interfacial region with the addition of Hastelloy X. During the tensile tests, the optimally built samples failed at the 316L side, implying the formation of solid bonding between the two metals.

Automated summary

The potential applications of steel/nickel bimetals in corrosive environments are becoming more and more interesting. In this study, a bimetallic 316L/Hastelloy X was processed using laser powder bed fusion (L-PBF) with different parameters. The results showed that the rapid cooling of L-PBF reduced element segregation and carbide formation, resulting in a crack-free interface. However, due to rapid solidification, the constituent elements of dissimilar materials were not properly mixed at the interface. The interfacial width increased with increasing laser energy density, and epitaxial grain growth was observed with the optimal processing parameters. The microhardness first declined at the front of the 316L side and then increased continuously in the interfacial region with the addition of Hastelloy X. The optimally built samples failed at the 316L side during tensile tests, indicating the formation of solid bonding between the two metals.