## 3 Results and Discussions
### Residual Stress in As-Built State
For this reason, distinguishing the retained austenite phase in the middle layer by the morphological difference of the phase was not possible. However, the electron backscatter diffraction map of the maraging steel in the as-built state showed significant unindexed areas, which indirectly indicate the possibility of very thin austenite phases existing in the martensite matrix in the middle layers [9]. To analyze the downward deformation behavior caused by the compressive stress at the top layer, finite element (FE) simulations were conducted using a two-dimensional plane stress model of the cantilever. Figure 3 shows the geometry and FE meshes used in these simulations. The simulation model consisted of the cantilever and the supporter legs. The artificial supporter was not modeled in the simulation since the supporter does not have any influence on the distortion of the cantilever in the simulation. The geometries of the cantilever and the supporter legs were set to be the same as in the experiments. As shown in Figure 3a, the top LPBF layer of the cantilever was considered as the fully martensite area. The thickness of the top layer was assumed to be 0.04 mm since the layer thickness of each layer was set to 0.04 mm in the LPBF experiment. For the FE calculations, the model was meshed with 49,720 FE nodes and 15,109 elements (Figure 3b). The maraging steel was assumed as a linear elastic material, with an elastic modulus and Poisson's ratio of 200 GPa and 0.33, respectively. The model was implemented on a commercial FE simulation package Ansys V19. Eight-noded 2D rectangular elements, Plane183 of Ansys, were used for the calculations. The simulations were carried out for the cantilevers while varying the thickness, \(T\), of the model. In the first step of the FE simulations, a compressive 600 MPa normal stress was applied along the cantilever beam direction (i.e., \(x\)-direction) at the top layer of the cantilever (i.e., fully martensite area in Figure 3a) by linearly expanding the layer by 0.3% along the beam direction. This condition was chosen because the phase transformation simulation predicted about a 600 MPa compressive stress state in the top layer when the layer was fully in the martensite state [23]. At this step, the bottom surfaces of the supporter legs were constrained. In the second step, the constraint of the bottom surface of each supporter leg was removed sequentially one by one, according to the cutting procedure  
Figure 2: (**a**) Deformation changes caused by cutting each leg of cantilevers with different thicknesses of \(T\), in as-built state. (**b**) Final deformations of cantilevers with different thicknesses after cutting all supporter legs. used in the experiment. The deformations of the cantilevers were determined by the vertical displacements of the top left edge of the model during the cutting process. Figure 4 shows the equivalent stress contours before and after cutting the supporter legs as calculated by the FE model for a 0.5 mm thick cantilever. Because the thickness of the top layer is much thinner than the total thickness of the cantilever, a significant compressive stress state exists only at the top layer while the rest of the cantilever has very low stress, except near the top left edge where a small amount of stress was transferred from the top layer to the region below due to the bending effect. When cutting the supporter legs, the compressive stress state at the top layer induces pronounced downward deformation of the cantilever, as expected. The deformations predicted by the FE model with various t are compared with the corresponding experimental results, as shown in Figure 5. Figure 5a shows comparisons of evolutions of the deformations while cutting the supporter legs, between the FE simulations and the experiments. The simulations show slightly different trends in the deformation compared with the experiments as the number of legs cut increases.