Effects of heat treatment and applied stresses on the corrosion performance of additively manufactured super duplex stainless steel clads
By Murkute, Pratik; Pasebani, Somayeh; Isgor, O. Burkan
Published in Materialia
Materialia
2020
Abstract
The super duplex stainless steel (SDSS) cladded low carbon steel (LCS) substrates manufactured via laser powder bed fusion technique (LPBF) have been recently developed to enhance the service life of the structural components in highly corrosive environments. As-printed (AP) SDSS clads showed predominantly ?-ferrite matrix with allotriomorphic austenite precipitating at the ferrite grain boundaries. Increasing scan speeds resulted in decreasing austenite phase fraction with a dominant widmannstatten morphology at higher scan speeds. Cladded composites were heat-treated to reduce the high residual and thermal stresses induced by the LPBF process, which decrease the corrosion resistance. Heat treatment restored the ?-? phase balance, thereby increased the corrosion resistance of the heat-treated (HT) clads as compared to AP clads. Increasing scan speeds resulted in decreasing corrosion resistance for the AP and HT clads. Subjecting the SDSS-LCS composite to tensile stresses increased the corrosion rates; however, these applied stress effects were eliminated by post stressing heat treatments, which restored the corrosion resistance of the clads. The SDSS clads produced at all scan speeds showed no signs of delamination from the LCS substrate, even at failure strains.