|About this Abstract
||Materials Science & Technology 2019
||Late News Poster Session
||P3-57: Unique Microstructure and Phase Transformation Behavior of High Carbon Tool Steel Layers Produced by Direct Energy Deposition Method
||Jongbae Jeon, Wookjin Lee, Sunmi Shin, Byungjun Kim
|On-Site Speaker (Planned)
Direct energy deposition (DED) method, one of the most widely-used AM methods, has potential to be used for repairing and surface modification of molds and broken parts, and recent studies carry out on the DED process of tool steels. However, microstructure evolution and phase transformation behavior of the deposited tool steel layers are dramatically different from bulk metals produced by conventional casting and heat treatment processes. The present study thus investigated the phase transformation of the deposited layers fabricated by DED process. The tool steel powder has a composition of M4-grade and was deposited on D2-grade substrate. It was found that in spite of rapid cooling rate, considerable amount of retained austenite was observed in room temperature, which is rarely found in the bulk M4-grade after conventional quenching process. Here we proposed underlying mechanism of this unique phase transformation behavior in the present tool steels deposited by DED process.