Microstructural evolution and mechanical characterization of wire arc additively manufactured 2Cr13 thin-wall part

Abstract

2Cr13 thin-wall part was additively deposited by robotic cold metal transfer (CMT) technology, and two traditionally manufactured counterparts in annealing (as-Aed) and quenching & tempering (as-QTed) conditions were adopted as comparison. The results show that only a strong texturing corresponding to α-Fe phase was detected for the wire-arc additively manufactured (WAAM) part, indicating an austenite-free structure. As-deposited microstructure was consisted of martensite laths and ferrite matrix, along with irregular δ-ferrite precipitation. The martensitic growth direction was non-oriented in the X–Y plane, but primarily parallel to the depositing direction in the X-Z and Y-Z planes along the maximum thermal gradient. Both nanohardness and ultimate tensile strength (UTS) for each WAAM sample were enhanced when compared with the as-Aed BM, while poorer than that of the as-QTed BM. Such mechanical evolution was a result of the intrinsic microstructural features, whereas the similar elastic modulus properties were mainly attributed to the similar 2Cr13 atomic bonding. A ductile tensile fracture behavior was dominant in the X-Z plane, while a mixed mode of ductile and brittle fracture occurred in the X–Y and Y-Z planes. The findings above reveal an isotropy in mechanical properties despite a slightly microstructural discrepancy in different planes for the as-deposited 2Cr13 WAAM part.

Keywords

• 2Cr13 thin-wall part
• Wire arc additive manufacturing
• Robotic cold metal transfer welding
• Microstructural evolution
• Mechanical properties