Effect of LaB6 addition on the microstructure and properties of (Ti3Al + TiB)/Ti composites by laser cladding

Yueqiao Feng; Kai Feng; Chengwu Yao; Zhuguo Li

Materials & Design (Nov 2019)

Effect of LaB6 addition on the microstructure and properties of (Ti3Al + TiB)/Ti composites by laser cladding

Yueqiao Feng,
Kai Feng,
Chengwu Yao,
Zhuguo Li

Affiliations

Yueqiao Feng: Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240, China
Kai Feng: Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240, China
Chengwu Yao: Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240, China
Zhuguo Li: Shanghai Key laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240, China; Shanghai Innovation Institute for Materials, Shanghai 200444, China; Corresponding author at: E-302A, School of Materials Science and Engineering, Shanghai Jiao Tong University, No.800 Dongchuan Road, Shanghai 200240, China.

Journal volume & issue: Vol. 181

Abstract

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An amount of LaB6 was added into the (Ti3Al + TiB)/Ti composites prepared on Ti6Al4V by laser cladding. The results showed that nano-scale La2O3 particles were formed through the in-situ reaction between La and O elements in the material system. With appropriate LaB6 addition (3.0%), the microstructure was refined and the second phase reinforcements were distributed more homogeneously. In addition, the oxygen elements in the coating were bound through the formation of La2O3, and the residual stress concentration was obviously reduced compared with that in the coating without LaB6 addition. However, the beneficial effect would be disappeared because of the tendency to create clusters when the additive content of LaB6 was excessive. During the solidfication process, the first generated La2O3 particles had a significant hetregeneous nucleation effect especially on the TiB phase in the coating. The grain refinement effect played the equally and even higher important role as the dispersion strengthening in the system. The microhardness and wear resistance of the coating with 3.0% LaB6 addition were improved. In addition, its high temperature oxidation resistance was also obviously increased, and the related mechanisms were discussed. Keywords: Laser cladding, Titanium alloy, Heterogeneous nucleation, Strengthening mechanism, LaB6 rare earth compound

Published in Materials & Design

ISSN: 0264-1275 (Print); 1873-4197 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Materials of engineering and construction. Mechanics of materials
Website: https://www.journals.elsevier.com/materials-and-design

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