Synthesizing Ti–Ni Alloy Composite Coating on Ti–6Al–4V Surface from Laser Surface Modification

Abstract

In this work, a Ni-alloy Deloro-22 was laser-deposited on a Ti–6Al–4V bar substrate with multiple sets of laser processing parameters. The purpose was to apply laser surface modification to synthesize different combinations of ductile TiNi and hard Ti2Ni intermetallic phases on the surface of Ti–6Al–4V in order to obtain adjustable surface properties. Scanning electron microscopy, energy dispersion spectroscopy, and X-ray diffraction were applied to reveal the deposited surface microstructure and phase. The effect of processing parameters on the resultant compositions of TiNi and Ti2Ni was discussed. The hardness of the deposition was evaluated, and comparisons with the Ti–6Al–4V bulk part were carried out. They showed a significant improvement in surface hardness on Ti–6Al–4V alloys after laser processing, and the hardness could be flexibly adjusted by using this laser-assisted surface modification technique.

Study on the Effect of Carburizing on the Microstructure and High-Temperature Oxidation Properties of Hot-Dip Aluminum Coating on Titanium Alloy

“…At 1050 • C, the Gibbs free energy of the three phases is less than zero, namely, ∆Gf < 0, indicating that the three compounds can be formed thermodynamically. The formation process of the alloy phase layer is 2TiAl 3 + 4Ti → Ti 3 Al + TiAl + 2TiAl 2 (11) The natural transition of the three newly formed phases (Ti 3 Al, TiAl, and TiAl 2 ) and TiAl 3 not only ensures the high-temperature oxidation resistance of the composite coating, but also enhances the interface bonding between the coating and the substrate and slows down the propagation of microcracks through the coating.…”

“…The formation of a Ti-Al diffusion coating on titanium alloy is a common method to improve its high-temperature oxidation resistance [7,8]. The Ti-Al diffused coating can be prepared by different processes, such as thermal spraying [9], aluminizing [10], laser surface alloying [11], the sol-gel method [12], and hot-dip aluminizing [7]. For example, Li, Z.W.…”

Study of the Performance of Laser Melting Wear-Resistant Coatings on TC4 Titanium Alloy Surfaces

“…Currently, scholars at home and abroad have conducted relevant research on the wear resistance of laser cladding WC reinforced Ni-based alloy powder composite coatings. Chen et al [13] studied the use of nickel-based alloy Deloro-22 for powder-blown laser cladding, and modified the surface of Ti-6Al-4V bars to TiNi/Ti2Ni-based intermetallic composites to improve the surface properties of Ti-6Al-4V. The results indicated that Deloro-22 nickel alloy powder can modify the Ti-6Al-4V surface by synthesizing various types of Ti x Ni y through laser processing.…”