The Effect Of Adding Elements On The Microstructure And Properties Of TiC/Ti6A14V Composites

In this paper, TiC particles reinforced Ti6A14V matrix composites had been fabricated using in-situ melting-casting process.The effect of C content and elements addition of B, Zr and Y on wear performance, compression performance and electrochemical corrosion of composites had been studied by scanning electron microscopy(SEM), X-ray diffraction(XRD), wear testing machine, universal material testing machine and electrochemical workstation.The results showed that TiC/Ti6A14V composites had better wear properties and compression properties than matrix alloy Ti6A14V. They showed that composites had better mechanical properties than matrix alloy. However, the corrosion resistance of composites was poorer than that of the matrix alloy.Properties of TiC/Ti6A14V matrix composites contacted with the content and morphology of enhanced phase TiC.TiC increased as the C content increased, and wear rate declined gradually. So wear resistance of composites improved. TiC dendrite fractured and became small when a small amount of alloying elements (B, Zr and Y) were added.And the TiC particles involving in wear were fewer, so wear resistance of composites declined; TiC dendrites were laeger(Adding Zr and Y) and TiB(Adding B) formed when appropriate elements were added.Therefor particles involving in wear increased and the wear resistance of composites improved. Hank's liquid lubrication could improve the wear resistance of composites significantly.With the increasing of TiC, TiC/Ti6A14V composites could bear the load better, so its compression performance at room temperature increased. Adding a small amount of elements (B, Zr and Y), which made TiC dendrite fracture and it is very helpful to improve the compression properties of composites. TiC dendrite became coarse and led to stress concentration easily When appropriate amount of Zr, Y element were added. So compressive properties of composites decreased. Adding the appropriate amount of B element would generate TiB, so compression performance of composites continued to improve. Fracture type of composites was typical brittle fracture.TiC/Ti6Al4V composites with the increasing of TiC could destroy the passivation film of the matrix alloy surface, so the corrosion resistance of composites declined. Adding a small amount of elements (B, Zr and Y), which made TiC dendrite fracture, and contact area between reinforced phase and matrix alloy increased, so the corrosion resistance of composites declined. When added an appropriate amount of Zr, Y element, TiC dendrite became coarse. And contact area between reinforced phase and matrix alloy became smaller, so the corrosion resistance of composites increased. Adding the appropriate amount of B element would generate TiB, so the passivation film of the matrix alloy surface was destroyed badly. Accordingly the corrosion resistance of composites continued to decrease.