Microstructural evolution of titanium matrix composite coatings reinforced by in situ synthesized TiB and TiC by laser cladding

Abstract

Titanium-based composite coatings reinforced by in situ synthesized TiB and TiC particles were successfully fabricated on Ti6Al4V by laser cladding using Ti-B 4 C-Al or Ti-B 4 C-C-Al powders as the precursor materials. The microstructural and metallographic analyses were made by X-ray diffraction (XRD), optical microscope (OM), scanning electron microscopy (SEM), and electron probe microanalysis (EPMA). The results show that the coatings are mainly composed of α-Ti cellular dendrites and a eutectic transformation product in which a large number of coarse and fine needle-shaped TiB and a few equiaxial TiC particles are homogeneously embedded. A thin dilution zone with a thickness of about 100 μm is present at the interface, and it consists of a few TiB and TiC reinforcements and a large number of lamella grains growing parallel to the heat flux direction in which a thin needle-shaped microstructure exists due to the martensitic transformation. The microstructural evolution can be divided into four stages: precipitation and growth of primary β-Ti phase, formation of the binary eutecticum β-Ti+TiB, formation of the ternary eutecticum β-Ti+TiB+TiC, and solid transformation from β-Ti to α-Ti.

In-situ synthesis of TiC/Ti composite coating by high frequency induction cladding

“…However, low hardness and modulus, poor wear resistance and high friction coefficient limit their applications, especially to the fields where specific surface performances are required [4][5][6]. Wear is essentially a surface-dependent property that may be improved by appropriate modification of the surface microstructures and compositions without affecting the properties of the bulk materials [7,8]. Titanium matrix composites (TMCs) have considerable potential, particularly for wear resistance applications because of their high hardness, high strength, high elastic modulus, and excellent high temperature stability.…”

The effect of using repetitively pulsed laser radiation in selective laser melting when creating a metal-matrix composite Ti-6Al-4V–B4C

“…In full accordance with previous studies [see. for example [18][19][20][21][22]], after laser melting of a mixture of B 4 C + Ti-6Al-4V powders, microstructural analysis based on SEM images clearly reveals the morphology of the phases being formed after solidi cation of the melt. Large (20-50 microns) fused particles of non-reactive ceramics B 4 C are observed (see Fig.…”

“…One of the most promising methods of creating a composition is the use of high-energy sources. In this case, both laser radiation [18][19][20][21][22][23][24] and an electric discharge arc [25][26][27][28] were used as energy sources.…”

“…The creation of MMC is possible by ex-situ synthesis (using TiC and TiB 2 powders) [29][30][31][32] or in-situ synthesis (using Ti and B 4 C or another precursor) [18][19][20][21][22][23]33]. It should be noted that a large number of works are devoted to the development of surface hardening methods by creating a metal-ceramic coating using the in-situ method for a TiC-TiB 2 mixture.…”

The Effect of using Repetitively Pulsed Laser Radiation in Selective Laser Melting when Creating a Metal Matrix Composite Ti-6Al-4V – B4C.

“…In full accordance with previous studies [see. for example [18][19][20][21][22]], after laser Note that such large TiB needles were studied in detail by Kooi et al [22]. Their complex structure and the presence of a hollow core lled, in particular, with titanium nuclei are shown.…”