Influence of Single Aging Treatment on the Mechanical Properties of Additively Manufactured Ultra-Thin 18Ni-300 Maraging Steel

In order to improve the performance of snow tires for automobiles, it is important to develop Kerf with an ultra-thin thickness under 0.4 mm. However, the reduced thickness requires further improved mechanical properties, such as strength, ductility and toughness. Therefore, we investigated the microstructure and mechanical properties by adjusting aging treatment conditions regarding 18Ni-300 maraging steel samples with an ultra-thin thickness of 0.4 mm, which were fabricated using the additive manufacturing technique, powder bed fusion (PBF) method. The microstructural analysis was performed using scanning-electron-microscope (SEM), electron-backscattered diffraction (EBSD) and transmission-electron-microscope (TEM). The mechanical properties were evaluated using the universal testing machine (UTM) with a strain rate of 1 × 10^− 3 s^− 1. It was found that after a single aging treatment without solution treatment, the microstructural evolutions, such as the formation of nano-precipitate and variation of volume fraction of reverted austenite were observed, which affect the strength and ductility, respectively. More specifically, the highest tensile strength of 1933.9 MPa was achieved in the sample aged at 480 ℃ for 3 h, whereas the maximum strain of 7.53% was obtained in the sample aged at 560 ℃ for 6 h. As a result, we report the aging treatment strategy to control the microstructure which can optimize the mechanical properties in the ultra-thin samples.