Microstructure and Wear Resistance of Multiscale TiN-Strengthened Ti6Al4V Composites Materials via Laser-Directed Energy Deposition
To improve the wear resistance of titanium alloy blades used in aircraft engines,three composite materials,namely micro-TiN/Ti6Al4V,nano-TiN/Ti6Al4V,and micro/nano-TiN/Ti6Al4V,were prepared via laser-directed energy deposition.Micro-TiN partially melted and dispersed within the Ti6Al4V matrix,leading to particle strengthening.Meanwhile,nano-TiN completely dissolved and solidified within the Ti6Al4V matrix,leading to solid solution strengthening.With variations in the melt-pool temperature and nitrogen content,primary and eutectic TixN phases formed in the nano-TiN/Ti6Al4V and micro/nano-TiN/Ti6Al4V structures,exhibiting dendritic,flower-like,and whisker-like microstructures that promoted grain refinement.The microhardness values(wear rates)of the micro-,micro/nano-,and nano-TiN/Ti6Al4V composite materials were 510 HV0.2(7.8 mg),565 HV0.2(6.9 mg),and 604 HV0.2(5.3 mg),respectively.Compared with that of Ti6Al4V,the microhardness values of micro-,micro/nano-,and nano-TiN/Ti6Al4V increased by 19.4%,32.1%,and 41.5%,respectively,and the wear rates decreased by 13.3%,23.3%,and 41.1%,respectively.Notably,nano-TiN/Ti6Al4V exhibited the highest microhardness value and optimal wear resistance.
laser directed energy depositionceramic strengtheningmicrostructurefriction and wear
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