Laser powder bed fusion of TiN - high nitrogen steel composite: Microstructure and strengthening mechanism

IF 6.1 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Science and Engineering: A Pub Date : 2025-02-01 DOI:10.1016/j.msea.2024.147595

Jiazhe Fu , Jie Liu , Jiahao Liu , Yaochun Zhou , Liang Fu , Linhai Fan , Yanwen Liang , Lixin Wang , Ying Xing , Kehong Wang

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引用次数: 0

Abstract

High nitrogen steel (HNS) produced by laser powder bed fusion (LPBF) has relatively excellent strength, but its ductility is poor. HNS + TiN is obtained by coating the HNS powder with the second phase, on the basis of which the changes in the microstructure of HNS + TiN formed via LPBF and the effects of the addition of the second phase on the mechanical property of HNS are systematically analyzed and the strengthening mechanism of HNS matrix composites is further elaborated. The microstructure of the samples formed via LPBF, HNS and HNS + TiN, are mainly composed of δ - ferrite and γ - austenite. The microstructures are characterized by changes in γ - austenite phase content, the average grain size after the addition of TiN, and the mechanical properties show changes, especially in ductility, with the elongation of the HNS + TiN sample reaching up to 16.25 %. and the average elongation is 3.3 times higher than that of HNS. The strengthening mechanism of the HNS + TiN is analyzed using EBSD, TEM and other characterization methods, the results show that Mn₂TiO₄ precipitates first at the grain boundaries and intracrystalline in the HNS + TiN, which plays a role in the second phase of solidification and grain refinement, and then the TiN is precipitated along the boundaries of Mn₂TiO₄. This study provides a new perspective to understand the relationship between microstructure and the mechanical properties of the HNS + TiN composite formed by LPBF, and provides a reference for the selection and application in LPBF in the future.

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来源期刊

Materials Science and Engineering: A 工程技术-材料科学：综合

CiteScore

11.50

自引率

15.60%

发文量

1811

审稿时长

31 days

期刊介绍： Materials Science and Engineering A provides an international medium for the publication of theoretical and experimental studies related to the load-bearing capacity of materials as influenced by their basic properties, processing history, microstructure and operating environment. Appropriate submissions to Materials Science and Engineering A should include scientific and/or engineering factors which affect the microstructure - strength relationships of materials and report the changes to mechanical behavior.