Effect of thermal cycles on microstructure of reduced activation steel fabricated using laser melting deposition
Qian An1, Zhi-xin Xia2, Chi Zhang1, Zhi-gang Yang1, Hao Chen1
1 School of Material Science and Engineering, Tsinghua University, Beijing 100084, China; 2 Shagang School of Iron and Steel, Soochow University, Suzhou 215021, Jiangsu, China
Effect of thermal cycles on microstructure of reduced activation steel fabricated using laser melting deposition
Qian An1, Zhi-xin Xia2, Chi Zhang1, Zhi-gang Yang1, Hao Chen1
1 School of Material Science and Engineering, Tsinghua University, Beijing 100084, China; 2 Shagang School of Iron and Steel, Soochow University, Suzhou 215021, Jiangsu, China
摘要 Reduced activation steel was successfully fabricated by laser melting deposition employing a Gaussian and a ring-shaped laser. The microstructure evolution of the reduced activation steel was investigated using the scanning electron microscope, transmission electron microscope and electron backscatter diffraction. The experimental results showed that the grains close to the substrate were smaller than the grains in the upper layers. Compared to those deposited using a Gaussian laser, the samples deposited using a ring-shaped laser showed a more homogeneous microstructure. Furthermore, a finite element analysis (FEA) model was applied to reveal the thermal history during laser melting deposition. The simulation results were well validated with the experimental results. FEA results indicate that the peak temperature increases and the cooling rate decreases, as the layer gets further from the substrate. Additionally, the temperature and the cooling rate resulting from the Gaussian laser model were higher at the midline of the samples and lower around the edges, whereas those of the ringshaped laser model were consistent with both at the center and around the edges.
Abstract：Reduced activation steel was successfully fabricated by laser melting deposition employing a Gaussian and a ring-shaped laser. The microstructure evolution of the reduced activation steel was investigated using the scanning electron microscope, transmission electron microscope and electron backscatter diffraction. The experimental results showed that the grains close to the substrate were smaller than the grains in the upper layers. Compared to those deposited using a Gaussian laser, the samples deposited using a ring-shaped laser showed a more homogeneous microstructure. Furthermore, a finite element analysis (FEA) model was applied to reveal the thermal history during laser melting deposition. The simulation results were well validated with the experimental results. FEA results indicate that the peak temperature increases and the cooling rate decreases, as the layer gets further from the substrate. Additionally, the temperature and the cooling rate resulting from the Gaussian laser model were higher at the midline of the samples and lower around the edges, whereas those of the ringshaped laser model were consistent with both at the center and around the edges.
Qian An,Zhi-xin Xia,Chi Zhang, et al. Effect of thermal cycles on microstructure of reduced activation steel fabricated using laser melting deposition[J]. Journal of Iron and Steel Research International, 2021, 28(03): 316-326.
2021, Vol. 28 
