Advanced search
Start date
Betweenand
Related content
(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Less-rigid coating in Ti obtained by laser surface alloying with Nb

Full text
Author(s):
Azevedo de Carvalho, Lisiane Rocha [1] ; Sallica-Leva, Edwin [1] ; Rayon Encinas, Emilio [2] ; Batista Fogagnolo, Joao [1]
Total Authors: 4
Affiliation:
[1] Univ Estadual Campinas, Sch Mech Engn, Rua Mendeleiev 200, BR-13083860 Campinas, SP - Brazil
[2] Univ Politecn Valencia, Inst Tecnol Mat, Camino Vera S-N, E-46022 Valencia - Spain
Total Affiliations: 2
Document type: Journal article
Source: SURFACE & COATINGS TECHNOLOGY; v. 346, p. 19-28, JUL 25 2018.
Web of Science Citations: 1
Abstract

The fabrication of parts with stiffness gradation specifically designed to attain higher mechanical and/or biomedical performance is receiving increasing scientific and technological interest. This work reports the use of laser surface alloying to introduce Nb into the surface layer of Ti pieces and thus obtain continuous coatings composed of Ti-Nb alloys. By controlling the laser processing parameters, coatings with lower Young's modulus and higher hardness compared to the substrate, practically free of cracks and with very low porosity were obtained, using energy densities in the range of 24 to 65 J/mm(2). However, compositional heterogeneity mainly due to microsegregation during the solidification process was observed. Increasing the energy density resulted in deeper fusion zones, which increased the substrate fusion and thus decreased the Nb content and produced a coating with a microstructure predominantly composed of alpha/alpha' acicular phase. On the other hand, the Nb content of the coatings produced with lower energy densities was high enough (similar to 20-30%(in) (mass)) to (meta) stabilize the less-rigid alpha{''} and beta phases, which promoted the highest reductions in the Young's modulus of the investigated coatings. Besides the lower stiffness, all coatings presented at least twice the hardness of the substrate. Maps of the properties constructed from the nanoindentation results showed that, despite the compositional heterogeneity, homogenous values of Young's modulus and hardness were attained and the change in the interface region was gradual, in agreement with the concept of functionally graded materials. (AU)

FAPESP's process: 11/19982-2 - Laser surface powder alloying of titanium with niobium and molybdenum
Grantee:João Batista Fogagnolo
Support Opportunities: Regular Research Grants