Grain refinement in additively manufactured ferritic stainless steel by in situ inoculation using pre-alloyed powder

SCRIPTA MATERIALIA

卷:194

Article

Durga, A.¹  Pettersson, Niklas Hollander¹  Malladi, Sri Bala Aditya²  Chen, Zhuoer²  Guo, Sheng²  Nyborg, Lars²  Lindwall, Greta¹ 

[1] KTH Royal Inst Technol, Dept Mat Sci & Engn, Brinellvagen 23, SE-10044 Stockholm, Sweden

[2] Chalmers Univ Technol, Ind & Mat Sci, SE-41296 Gothenburg, Sweden

关键词: Laser Powder-Bed Fusion;    Columnar-to-equiaxed transition;    Inoculation;    Solidification;    Ferritic stainless steels;   

DOI  :  10.1016/j.scriptamat.2020.113690

来源: Elsevier

【 摘 要 】

For ferritic stainless steels, TiN has effectively been used as an inoculant to produce equiaxed grain structures in casting and welding. However, it is not established whether TiN would be an effective inoculant in additive manufacturing. In this study, the effectiveness of TiN as an inoculant in a ferritic stainless steel processed by laser powder-bed fusion is studied. An alloy without Ti is fabricated and compared to an alloy designed to form a high amount of TiN early during solidification. The work shows that the presence of TiN provides general grain refinement and that TiN-covered oxide particles are effective in enabling columnar-to-equiaxed transition in certain regions of the meltpool. The applied approach of pre-alloying powders with inoculant-forming elements offers a straightforward route to achieving fine, equiaxed grain structures in additively manufactured metallic materials. It also shows how oxygen present during the process can be utilized to nucleate effective inoculating phases. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd.

【 授权许可】

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