Microstructures and mechanical behavior of beta-type Ti-25V-15Cr-0.2Si titanium alloy coating by laser cladding
Materials Science and Engineering A
School of Engineering
National Key Research and Development Program of China Natural Science Basic Research Plan in Shaanxi Province of China Fundamental Research Funds for the Central Universities
© 2020 Preparing a flame-resistant coating with high adhesion to the titanium substrate is a feasible method to prevent “titanium fire”. In this work, Ti-25V-15Cr-0.2Si, which is a beta stabilized titanium alloy with excellent flame-resistant properties, was fabricated on a Ti-6Al-4V substrate by laser cladding with aim to improve the flame resistance of the Ti-6Al-4V substrate. The microstructure, mechanical properties and strengthening mechanisms of the laser cladded samples were studied. An excellent metallurgical bond is formed between the substrate and the cladded layers and a reasonable transition of composition and microhardness from the substrate to the Ti-25V-15Cr-0.2Si cladded layers is obtained. An effective relationship between dilution ratio and composition was established to predict the composition evolution of transition zone in the cladded layers. Microstructural characterization confirmed a direct transformation from α+β bi-phase in Ti-6Al-4V substrate to single β phase in Ti-25V-15Cr-0.2Si laser cladded zone throughout the cladding interface. The room-temperature tensile testing along both parallel and vertical to cladding interfaces showed that the cladded samples exhibit tensile strength exceeding 900 MPa and elongation of > 9% (reaching 90% and 70%, respectively, the corresponding ones of wrought Ti-6Al-4V substrate), indicating the very good mechanical performance of the laser cladded samples.