Build atmosphere aided texture control in additively manufactured FeCrAl steel by laser powder bed fusion

Through properly selecting the process atmosphere, involving pure argon gas (Ar) and nitrogen gas (N₂), we have achieved the in-situ texture control of laser powder bed fusion (LPBF)-manufactured FeCrAl parts with fixed process parameters. The results, from crystallographic orientation analysis, indicate that a single crystalline-like microstructure is developed under the N₂ process atmosphere while printing under the common Ar case results in a chessboard-like microstructure composed of strong fiber texture with 〈111〉 along the Z-axis (building direction) and cube texture with 〈001〉 parallel to X-, Y-, and Z-axes. The texture control mechanism under different process atmospheres has been elucidated by extracting the corresponding molten pool morphology information, that is flat molten pool for the N₂ process atmosphere but keyhole one for the Ar case. The current findings demonstrate the feasibility of utilizing the process atmosphere of additive manufacturing to manipulate the crystallographic texture of metals.