INCREASING FATIGUE STRENGTH AND WEAR RESISTANCE OF ADDITIVE MANUFACTURED NICKEL ALLOY (UNS N07718) BY ULTRASONIC NANOCRYSTAL SURFACE MODIFICATION (UNSM) TREATMENT

摘要

Additive Manufacturing (AM) which is also known as metal 3D printing technique is a promising process with a massive potential for developing a component for wide range applications for various industries. Recently, AM process was introduced to the nuclear power plant industry as AM is capable of manufacturing the substitution of aging and obsolete component. However, the AM component has inferior mechanical properties and performance in terms of fatigue strength and wear resistance compared to its conventionally manufactured counterpart. Ultrasonic Nanocrystal Surface Modification (UNSM) is one of mechanical surface modification treatment known for improving fatigue strength and wear resistance of wrought material. Hence, in this study effect of UNSM treatment on fatigue strength and wear resistance of additive manufactured material was investigated. The investigation was done to Ni-based alloy 718 (UNS N07718) as this material is used for nuclear power plant components and was manufactured with two different AM techniques namely Powder Bed Fusion (PBF) and Direct Energy Deposition (DED) processes. The evaluation was conducted by comparing the as-polished and UNSM-treated specimens for each AM processes by performing fatigue and tribo tests. This result will become a part of the technical basis for KEPJC Code Case development.