Abstract

Refinement of as-cast structures is one of the most effective approaches to improve mechanical properties, formability, and surface quality of steel castings and ingots. In the past few decades, addition of rare earths (REs), lanthanum and cerium in particular, has been considered as a practical and effective method to refine the as-cast steels. However, previous reports contained inconsistent, sometime even contradictory, results. This review summaries the major published results on investigation of the roles of lanthanum or/and cerium in various steels, provides reviews on the similarity and difference of previous studies, and clarifies the inconsistent results. The proposed mechanisms of grain refinement by the addition of lanthanum or/and cerium are also reviewed. It is concluded that the grain refinement of steels by RE additions is attributed to either heterogeneous nucleation on the in-situ formed RE inclusions, a solute effect, or the combined effect of both. The models/theories for evaluation of heterogeneous nucleation potency and for solute effect on grain refinement of cast metals are also briefly summarized.

Details

Title
Roles of Lanthanum and Cerium in Grain Refinement of Steels during Solidification
Author
Ji, Yunping 1 ; Ming-Xing, Zhang 2 ; Ren, Huiping 1 

 School of Material and Metallurgy, Inner Mongolia University of Science and Technology, Baotou 014010, China; School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China 
 School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD 4072, Australia 
First page
884
Publication year
2018
Publication date
2018
Publisher
MDPI AG
e-ISSN
20754701
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2582835015
Copyright
© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.