Microstructure and oxidation properties of TF550 alloy by laser cladding and ultrasonic impact hybrid manufacturing.

In this paper, ultrasonic impact treatment (UIT) and laser cladding TF550 alloy was combined to achieve the purpose of refining grains and improving oxidation performance. The results showed that after UIT, the porosity decreased from 8.47 % to 3.59 %, grain size of the equiaxed grain at the top area decreased to about 18 μm, but the width of the equiaxed grain region increased. The number of equiaxed grains at the bottom of the ultrasonic impact specimen increased, and the middle part was still columnar grain structure. The average size was about 88μm, which was about 66 % lower than that of the unimpacted specimen. In addition, compared with the sample without UIT, the ablation pit area of the sample with UIT decreased by 35.99 %, 31.58 % and 34.71 %, respectively. The content of O element decreased to about 50 %, and the content of Ti, V and Cr elements increased as a whole. The oxidation degree of the sample surface decreased and the ablation resistance increased. And the oxidation weight gain was lower after UIT, which was 7.5 % lower than that of the unimpacted sample. The thickness of the oxide film was reduced and the antioxidant properties were enhanced. • After UIT, the height of the cladding layer is reduced, the microstructure is refined. • After UIT, the ablation crack propagation of the sample is reduced, burn resistance performance is improved. • After UIT, the oxidation rate of the sample decreased, high temperature oxidation resistance was improved. [ABSTRACT FROM AUTHOR]