Effects of Heat Treatment on the Microstructure, Mechanical Properties and Corrosion Behavior of 2209 Duplex Stainless Steel Parts Manufactured By Wire Arc Additive Manufacturing Process

The present study deals with the fabrication and investigation of structure, microstructure, mechanical properties and corrosion resistance of 2209 duplex stainless steel parts made by wire arc additive manufacturing method. The formation of ferrite and austenite phases was confirmed by XRD analysis. There was a non-uniform distribution of ferrite and austenite phases in the microstructure of the as-welded microstructure. The tensile and Vickers microhardness tests were employed to evaluate mechanical properties. The results showed that the mean values of yield and tensile strengths were respectively 2.7 and 5.5% higher and the elongation was 4.5% lower in the welding direction than the building direction. Post-processing heat treatment at 1000 °C for 30 min led to the grain refinement of the alloy, the formation of equiaxed microstructure, increase in the austenite volume fraction, and increasing the mean hardness from 318 to 376 HV. The fractography of the tensile test specimens revealed the ductile fracture mode in all samples. Corrosion test results showed that the heat treatment improved the corrosion resistance of the alloy.