Effect of ultrasonic intensity on microstructure and mechanical properties of steel alloy in direct energy deposition-Arc

• Published in: Ultrasonics Vol. 134; p. 107090
• Main Authors: Ji, Feilong, Qin, Xunpeng, Ni, Mao, Hu, Zeqi, Wu, Mengwu
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-09-2023
• Subjects: Different ultrasonic intensity; Direct energy deposition-Arc; Grain refining; Mechanical properties; Molten pool solidification; Mechanical properties; Direct energy deposition-Arc; Different ultrasonic intensity; Grain refining; Molten pool solidification
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/j.ultras.2023.107090

•The effect of different ultrasonic intensity on grain refinement of deposition layer was investigated by an improved ultrasound assisted direct energy deposition-Arc system.•The propagation and distribution of ultrasonic in the substrate was simulate to determine the deposition position.•The microstructure refinement of the deposition part was studied using optimized ultrasonic parameters, yield strength and tensile strength improved by 10.9% and 10.7%, respectively.
To study the effect of ultrasonic intensity on the microstructure and mechanical properties during the direct energy deposition-Arc (DED-Arc) of ER70S-6 steel alloy, an ultrasound assisted DED-Arc system was developed by coupling ultrasonic energy with the electric arc deposition process. The propagation and vibration distribution of ultrasound in the substrate were analyzed by numerical simulation method. Deposition layers were fabricated using different ultrasonic amplitudes, and the microstructure, microhardness and tensile properties of the fabricated parts were systematically investigated. The results show that as the ultrasonic intensity increased, the grain refinement area expanded from the center of the molten pool to the surrounding area, and the grain morphology transforms from coarse columnar grains to fine equiaxed grains. When the ultrasonic amplitude was 15 μm, the grain refinement area of the cross-section was 94.6%, the average grain size was significantly increased to about grade 6. The microhardness increased by 10.6%. Thousands of ultrasonic cavitation events not only enhance the supercooling and wettability of the melt pool to promote nucleation, but also break the columnar grains into small grains by intense shock waves, which significantly improve the microstructure homogeneity and mechanical properties. The research provides an alternative approach to overcoming the long-standing problem of coarse columnar grains in the field of DED-Arc.