Preferential orientation and mechanical properties anisotropy of wire and arc additive manufactured duplex stainless steel

Abstract

Wire and arc additive manufacturing (WAAMing) is a highly efficient way to fabricate metal parts. In this work, the 2209 duplex stainless steel (DSS) was WAAMed using cold metal transfer (CMT) method. The anisotropy of WAAMed 2209DSS was systematically discussed based on the characterization of microstructure and mechanical properties. The results showed that the prior ferrite had a strong anisotropy. The 〈100〉 crystal direction had a preferential orientation in building direction (BD). The 〈110〉 crystal direction had a preferential orientation in welding direction (WD) and transverse direction (TD). The austenite had a KS relationship on the orientation with ferrite. The tensile samples were machined in three crystal direction of prior ferrite, including <100> in BD, <110> in WD, and 〈111〉. The tensile sample in 〈111〉 showed the largest ultimate tensile strength (UTS). According to the variation of Schmid factors, the ferrite in <111> had the smallest Schmid factor in {110}〈111〉 slipping system. It yielded a larger stress for dislocation movement and contributed to the largest UTS. The tensile sample in <100> achieved the largest elongation as the larger Schmid factor of ferrite in {110}<111 > slipping system and austenite in {111}〈110〉 slipping system. In addition, the centrosymmetry of orientation around the axis of tensile sample in <100> weakened the stress concentration and helped a more uniform elongating.