Influence of the heat treatment temperature on the MAO coating produced in the Ti-25Ta-25Zr alloy

Author(s)

Kuroda, Pedro Akira Bazaglia ; de Mattos, Felype Narciso ; Grandini, Carlos Roberto ; Afonso, Conrado Ramos Moreira

• Document type: Journal article
• Source: JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T; v. 26, p. 12-pg., 2023-08-28.

Abstract

The main objective is to carry out several heat treatments to change the phases and some characteristics of the MAO coatings formed in Ti-25Ta-25Zr alloy in order to understand how the oxides or morphology of the MAO coating influence hardness, elastic modulus, adhesion, and wear resistance. The results showed that the MAO coating is amorphous and constituted by TiO2, ZrO2, Ta2O5, and CaCO3, and the heat treatments promoted the formation of Ti2O3 and CaO and the degradation of Mg at 800 degrees C. Increasing the temperature of the heat treatments reduced the pore size and, consequently, decreased roughness (minimum value of 0.77 mm in the condition of 500 degrees C), increased hardness (maximum of 673 HV), and improved wear resistance (3 x 10(-15) m/N-1).When heat treatments are carried out above 600 degrees C, cracks are observed throughout the coating. Under these conditions, the roughness is altered and is no longer influenced only by pores size. Cracks increase the roughness of the coatings, reaching a maximum value of 1.16 mm. Therefore, there is a decrease in the coatings' hardness, and the alloy becomes more sensitive to abrasive wear phenomena. At 800 degrees C, the hardness is 494 HV, and the wear rate similar to 40 x 10(-15) m(2)/N Regarding elastic modulus, the Ti-25Ta-25Zr alloy with the MAO coating subjected to heat treatment at 400 degrees C has a lower elastic modulus. Coatings subjected to high temperatures (above 500 degrees C) have an HF1 rating indicating high adhesion. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). (AU)

• FAPESP's process: 18/18293-8 - Titanium alloys: phase transformations and additive manufacturing applied to obtaining functionally graded materials
• Grantee: Rubens Caram Junior
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 19/26517-6 - Influence of the microstructure and phases on surface functionalization of beta Ti-25Ta-xZr- alloys system
• Grantee: Pedro Akira Bazaglia Kuroda
• Support Opportunities: Scholarships in Brazil - Post-Doctoral