Laser Cladding of an In Situ Synthesized TiB and TiC Reinforced Titanium Matrix Composite Coating on Ti6Al4V
A titanium matrix composite coating reinforced by in situ synthesized TiB and TiC was deposited on Ti6Al4V by laser cladding. Microstructural analyses were made by means of X-ray Diffraction (XRD), Optical Microscopy (OM), Scanning Electron Microscopy (SEM) and Electron Probe Micro-Analysis (EPMA). The solidification process was also discussed in detail. The results show that the coating is composed of -Ti cellular dendrites and a eutectic in which a large number of needle-shaped TiB whiskers and a few equiaxial TiC particles are embedded. A thin dilution zone with a thickness of 50 m is observed at the interface, and consists of a few TiB and TiC and a large number of lamella grains in which a thin needle-shaped martensitic microstructure is exist. The solidification process could be divided into four stages: nucleation and growth of primary -Ti phase, precipitation of a binary eutectic -Ti+TiB, precipitation of a ternary eutectic -Ti+TiB+TiC and solid transformation from -Ti to -Ti.
Zhengyi Jiang and Chunliang Zhang
J. Li et al., "Laser Cladding of an In Situ Synthesized TiB and TiC Reinforced Titanium Matrix Composite Coating on Ti6Al4V", Advanced Materials Research, Vols. 97-101, pp. 3861-3865, 2010