Microstructures and mechanical properties of reduced activation ferritic/martensitic steel fabricated by laser melting deposition

Feng, Junyi and Zhang, Peilei and Jia, Zhiyuan and Yu, Zhishui and Fang, Chao and Yan, Hua and Shi, Haichuan and Tian, Yingtao (2021) Microstructures and mechanical properties of reduced activation ferritic/martensitic steel fabricated by laser melting deposition. Fusion Engineering and Design, 173. ISSN 0920-3796

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Abstract

Laser melting deposition (LMD) is a promising way for the fabrication of complex reduced activation ferritic/martensitic (RAFM) steel components which provides an exceptional opportunity to improve the existing designs and move toward fabricating fine features and complex geometries with higher efficiencies. It is well known that if steel members are welded together, defects will be concentrated in the welded joint. We can control the scanning path of the laser to achieve a complex component molding, avoiding welding. Considering the LMD technology, the results of each layer of powder molding will affect the fineness of the final processed products, such as laser power, scanning speed, defocus and so on, which are all important factors affecting the products. We control the size of powder particle size as a variable to conduct a study on RAFM steel supplemented by LMD technology for the first time, and its microstructure and grain size were analyzed. In terms of mechanical properties, its hardness, Charpy impact, tensile strength and elongation were measured. The results show that compared with other processing processes including Selective Laser Melting (SLM), rolling, welding joints, the tensile strength of RAFM steel manufactured by laser coaxial powder feeding is up to 1057.75 MPa, and there are no pores and almost no defects when using small particle size powder. The microstructure of LMD RAFM steel contains a large amount of lath martensite and δ-ferrite, and some precipitates such as Mx, whose average grain size decreases with the increase of powder particle size (5–150 μm). In this study, the laser additive process was monitored by high-speed photography, and the average grain size of LMD RAFM steel was further analyzed, and a reasonable explanation of its mechanical properties was given.

Item Type:
Journal Article
Journal or Publication Title:
Fusion Engineering and Design
Additional Information:
This is the author’s version of a work that was accepted for publication in Fusion Engineering and Design. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Fusion Engineering and Design, 173, 2021 DOI: 10.1016/j.fusengdes.2021.112865
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2100/2104
Subjects:
ID Code:
159589
Deposited By:
Deposited On:
13 Sep 2021 14:45
Refereed?:
Yes
Published?:
Published
Last Modified:
06 Oct 2021 08:28