Solidification structure and high temperature oxidation resistance of nano titanium dioxide TiO2 added Inconel 718 deposits by arc melt

Abstract

In order to refine the microstructure of Inconel 718 and achieve high performance, nanometer TiO _2 particles (nano-TiO _2 ) were adopted to modify the solidification structure. After pretreating nano-TiO _2 , oxide added 718 nickel alloy were prepared by using arc melting technology, and the microstructure and oxidation behavior were investigated in detail. The results show that the microstructures of Inconel 718 alloys with different content of nano-TiO _2 are all dendritic-like, and the size of dendrite gradually decreases and the shape tends to become equiaxed grain with the increase of TiO _2 content. The grain refinement effect is best for 0.6%TiO _2 added alloy. The precipitated phases become finer and more uniform due to grain refinement. The high temperature oxidation experiments of Inconel 718 alloy with different volume fractions of TiO _2 show that the main oxides are Cr _2 O _3 , accompanying with some Nb-Fe oxides. With the decrease of grain size, the size of oxides gradually decreases, and the oxidation layers are more and more compact, which effectively improves the oxidation resistance.

Keywords

• inconel 718
• nano-TiO2
• grain refinement
• high temperature oxidation resistance
• oxidation kinetics