The analysis of ultrasonic impact on mechanical and tribological properties of stainless steel during direct metal deposition process

In this paper, the process of direct laser deposition of stainless steel specimens with ultrasonic exposure is studied. Three groups of specimens were prepared according to the developed growth strategies to investigate the mechanical and tribological characteristics. It was found that additional ultrasonic exposure leads to an increase in the hardness of the deposited layers by 8.2 %. At the same time, the hardness of the main metal zone does not undergo significant changes. The results of tensile strength tests show an increase in the average strength value by 44.3 MPa, which is equivalent to 8.9 %. Studies of the tribological characteristics showed that the wear resistance of the specimens obtained with ultrasonic exposure increased by 26.3 %. The introduction of ultrasonic vibrations is associated with changes in the microstructure and structure of the melt pool flows. These changes are presumably caused by the cavitation effect and acoustic streaming.