Microstructure and Property Analysis of AerMet100 Steel Manufactured by In-situ Rolling Mixed Wire Arc Additive Manufacturing

Aer Met100 steel thick wall is fabricated by in-situ rolling composite wire arc additive manufacturing(WAAM).The microstructure and mechanical properties of Aer Met100 steel after heat treatment are studied.The results show that after the introduction of in-situ rolling force,the grain of Aer Met100 steel is broken,the anisotropy is eliminated,and the microstructure is refined obviously.The microstructure of Aer Met100 steel after heat treatment is mainly lath martensite and reverse austenite.There are 40 nm-68.6 nm alloy carbides precipitated in the martensitic matrix,and the hardening mechanism is mainly Orowan bypass strengthening.The film-like reverse austenite with the thickness ranging from 2 nm to 5 nm exists between the martensitic lath,which improves the toughness of the maraging steel.Good combination of strength and toughness can be achieved through proper heat treatment process.