scholarly journals Machining and heat treatment as post-processing strategies for Ni-superalloys structures fabricated using direct energy deposition

2021 ◽  
Vol 61 ◽  
pp. 236-244
Author(s):  
Francesco Careri ◽  
Stano Imbrogno ◽  
Domenico Umbrello ◽  
Moataz M. Attallah ◽  
José Outeiro ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Energy Deposition ◽  
Post Processing ◽  
Direct Energy Deposition ◽  
Processing Strategies ◽  
Direct Energy

scholarly journals Influence of Direct Energy Deposition Parameters on Ti–6Al–4V Component’s Structure-Property Homogeneity

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 887
Author(s):  
Chan Hyeok Lee ◽  
P. L. Narayana ◽  
Seong-Woo Choi ◽  
N. S. Reddy ◽  
Jae H. Kim ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Process Parameters ◽  
Energy Deposition ◽  
Mechanical Characteristics ◽  
Structure Property ◽  
Ann Model ◽  
Direct Energy Deposition ◽  
Specific Strength ◽  
Direct Energy ◽  
Artificial Neural Network Ann

Ti–6Al–4V alloy is a typical 3D printing metal, and its application has been expanded to various fields owing to its excellent characteristics such as high specific strength, high corrosion resistance, and biocompatibility. In particular, direct energy deposition (DED) has been actively explored in the fields of deposition and the repair of large titanium parts. However, owing to the complicated thermal history of the DED process, the microstructures of the fusion zone (FZ), heat-affected zone (HAZ), and base metal (BM) are different, which results in variations of their mechanical characteristics. Therefore, the process reliability needs to be optimized. In this study, the microstructure and hardness of each region were investigated with respect to various DED process parameters. An artificial neural network (ANN) model was used to correlate the measured characteristics of the FZ, HAZ, and BM of Ti–6Al–4V components with the process parameters. The variation in the mechanical characteristics between the FZ, HAZ, and BM was minimized through post-heat treatment. Heat treatment carried out at 950 °C for 1 h revealed that the microstructure and hardness values throughout the component were homogeneous.

scholarly journals Effect of Post-Weld Heat Treatment on Microstructure and Hardness Evolution of Functionally Graded Materials Produced by Direct Energy Deposition

2021 ◽  
Vol 59 (2) ◽  
pp. 81-98
Author(s):  
Giseung Shin ◽  
Yongho Park ◽  
Dae Whan Kim ◽  
Ji hyun Yoon ◽  
Jeoung Han Kim
Keyword(s):  
Heat Treatment ◽  
Energy Deposition ◽  
Lath Martensite ◽  
Bainitic Ferrite ◽  
Post Weld Heat Treatment ◽  
Functionally Graded ◽  
Direct Energy Deposition ◽  
Type 316L ◽  
Direct Energy ◽  
Weld Heat

In this work, the effects of post weld heat treatment (PWHT) on the microstructure and mechanical properties of functionally gradient materials (FGM) was investigated. The FGM consisted of five different layers which were mixtures of austenitic stainless steel (type 316L) and ferritic steel (LAS). The ratio of type 316L and LAS powder in each deposition layer was 100:0, 75:25, 50:50, 25:75, and 0:100. FGM samples were successfully fabricated without cracks or delamination by a direct energy deposition process. The sensitization phenomenon of the FGM samples was investigated after PWHT. The PWHTs were conducted at 700<sup>o</sup>C, 900<sup>o</sup>C, and 1100<sup>o</sup>C for 4 hours and the samples were then air-cooled. After PWHT, the annealed specimens were observed by optical and scanning electron microscopy to analyze their microstructure. The occurrence of sensitization was found in the specimen annealed at 700<sup>o</sup>C. The contents of Cr and C increased substantially along grain boundaries. However, the sensitization did not occur in other samples annealed at 900<sup>o</sup>C and 1100<sup>o</sup>C. In the C and D layers of the 1100<sup>o</sup>C annealed sample, micro-hardness was measured to be very high due to the formation of bainitic ferrite and a lath martensite structure. In addition, a reduction of the austenite fraction was confirmed by Electron Back Scatter Diffraction.

Multi-physics modeling of direct energy deposition process of thin-walled structures: defect analysis

2021 ◽  
Vol 67 (4) ◽  
pp. 1229-1242
Author(s):  
Shuhao Wang ◽  
Lida Zhu ◽  
Yichao Dun ◽  
Zhichao Yang ◽  
Jerry Ying Hsi Fuh ◽  
...  
Keyword(s):  
Energy Deposition ◽  
Deposition Process ◽  
Defect Analysis ◽  
Direct Energy Deposition ◽  
Thin Walled Structures ◽  
Direct Energy ◽  
Thin Walled ◽  
Physics Modeling
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