Effect of rapid cooling of high temperature laser fabricated Ti/B4C/BN coating on Ti-6AL-4V alloy

Abstract: A hybrid Ti-6Al-4V based metal matrix composites characterized of martensitic structure was formed using three hoper system. Different volume percentages used were as follows: 3.0 vol. % of Ti-6Al-4V, 3.2 vol. % of Ti-6Al-4V and 3.4 vol. % of Ti-6Al-4V respectively while an equal amount of BN and B4C mixed with the Ti-6Al-4V powder particle was fed through the hoper systems at a constant laser power 2000 W and scanning speed of 1.0 m/s. The influence of rapid cooling and varied powder particle at constant coating temperature on the surface morphology and hardness property of Ti-6Al- 4V/B4C/BN alloy systems was however investigated. The hardness result of experimental showed a general improvement. Further result showed that the Ti-6Al- 4V/B4C/BN system fabricated at 3.0 Ti Vol. percent had a hardness improvement as high as 986.9 HVO.5 compared to the as receive Ti-6Al-4V substrate Hardness value of about 357.3 HVO.5. 3.2 Ti Vol. percent systems recorded a hardness value of 723.4 HVO.5 and 3.2 Ti Vol. percent system recorded a hardness value of 609.6 HVO.5. Optical microscope (OM) Scanning electron microscope (SEM) was also carried out for microstructural evaluation and Energy Dispersive Spectroscopy (EDS) to confirm the elemental composition of coating when necessary