scholarly journals Effects of thermal undercooling and thermal cycles on the grain and microstructure evolution of TC17 titanium alloy repaired by wire arc additive manufacturing

Author(s):  
Yimin Zhuo ◽  
Chunli Yang ◽  
Chenglei Fan ◽  
Sanbao Lin
2021 ◽  
Author(s):  
Yimin Zhuo ◽  
Chunli Yang ◽  
Chenglei Fan ◽  
Sanbao Lin

Abstract Wire arc additive manufacturing (WAAM) can be used to repair blades or blisk made of titanium alloy with the advantage of high efficiency and low-cost. In this work, the finite element model of repairing the blade based on the arc heat source was established to investigate it. Results showed that the maximum effect of thermal undercooling appears when the peak current transforms to the base current (1Hz or 5Hz), which will promote the grains refinement with the combination of sufficient constitutional supercooling. Compared to the single-layer deposition, the microstructure in the near-heat affected zone (near-HAZ) of multi-layer deposition changes from the metastable β phases to the extremely fine α phases, which was caused by the repeated thermal cycles.


2021 ◽  
Author(s):  
Mohamed Belhadj ◽  
Sana Werda ◽  
Asma Belhadj ◽  
Robin Kromer ◽  
Philippe Darnis

Wire arc additive manufacturing process (WAAM) is an innovative technology that offers freedom in terms of designing functional parts, due to its ability to manufacture large and complex workpieces with a high rate of deposition. This technology is a metal AM process using an electric arc heat source. The parts manufactured are affected by thermal residual stresses due to high-energy input between wire and workpiece despite numerous advantages with this technology. It could cause severe deformation and change the global mechanical response. A 3D transient thermal model was created to evaluate the thermal gradients and fields during metal deposition. The material used in this study is a steel alloy (S355JR-AR). This numerical model takes into account the heat dissipation through the external environment and the heat loss through the cooling system under the base plate. Birth-element activation strategy was used to generate warm solid part following the movement of the heat source. The metal deposition is defined with constant welding speed. Goldak model was used to simulate the heat source in order to have a realistic heat flow distribution. Results were in concordance for thermal cycles at different points comparing with experimental results issued from bibliography in terms of: (1) Temperature maximum, (2) Thermal cycles and (3) Cooling gradient phase. This study enabled to check the numerical model and used as a predictive tool


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