Multi-material stainless steel fabrication using plasma wire arc additive manufacturing

Layered stainless steel samples were manufactured using Plasma Wire Arc Additive Manufacturing by depositing alternating layers of two dissimilar stainless steels onto an AISI 316L substrate. The selected materials were the M430 ferritic and M316L austenitic stainless steels. Comprehensive microstructural characterization in different areas, including interfaces between the two different materials, was achieved through optical microscopy and electron backscatter diffraction. Results revealed good weldability among the two-layered steels and on the substrate. Also, a gradient duplex structure was observed mainly at the layer interfaces, suggesting a nuanced blending of properties in the deposited zone. To establish a direct correlation with mechanical properties in the observed structures, macro and micro-hardness tests were conducted along the cross-section. These tests evidenced the presence of a harder phase along the interface compared to the individual materials. The microstructural analysis corroborated the presence of mixing between phases in conjunction with some areas of delta ferrite.