Thermal-induced microstructural evolution and defect distribution of wire-arc additive manufacturing 2Cr13 part: Numerical simulation and experimental characterization

Abstract

Both of the transient thermal transfer model and the thermal elastic-plastic model were adopted for the thermal and stress simulation during the additively manufacture of 2Cr13 thin-wall part. The microstructural evolution and internal defect distribution were also characterized, as well as the measurement of thermal cycles and residual stress. A fair agreement between the simulated and experimental results, including the thermal cycling curves and residual stress distribution, was achieved. During the arc deposition, the spatially transient stress distribution was evolved regularly as a consequence of the repeated transient thermal history, which finally transformed into the residual stress within the whole part and caused the wrapping phenomenon. In the middle region, the location-related metal-stable microstructure and nonhomogeneous micro-sized pore distribution was obtained within a single layer, supposedly a result of complicated in-situ micro-heating treatment when new layers continuously deposited on the top of the buildup. However, the whole top-most layer was featured by the homogenous microstructure and pore distribution, as this area didn’t undergo the further in-situ thermal cycle. The intrinsic relationship of “thermal history- microstructural evolution- defect distribution” was explored with the combination of numerical simulation and experimental characterization during the arc deposition of 2Cr13 part.