Microstructure And Properties Of Cr₃Si/TiC/Inconel 718 Composites Fabricated By Plasma Melting Deposition Manufacturing Process

The turbine blade tenon part of the engine turbine disc is subjected to high temperature fretting wear for a long time while being subjected to complex stress.It is required that the blade should have excellent high temperature endurance strength and good high temperature wear resistance.A single high-temperature alloy material does not have so many excellent properties,and the development of advanced high-temperature alloy matrix composite materials with excellent comprehensive high-temperature mechanical properties and good high-temperature wear resistance has become aIn this paper,the composition ratio?wt.%?is Inconel 718-Cr50.4-Si9.6,Inconel718-Cr58.8-Si11.2,Inconel 718-Cr58.8-Si11.2-Ti8.3-Ni-coated graphite1.7,Inconel718-Cr54.6-Si10.4-Ti12.5-Ni-coated graphite 2.5 and Inconel 718-Cr50.4-Si9.6-Ti16.7-Ni-coated graphite3.3 series of mixed powders are used as raw materials,and the transition group metal silicide Cr₃Si with high melting point,high modulus,high temperature hardness and excellent high temperature wear resistance is prepared by plasma melting deposition manufacturing for high temperature wear reinforced phase,the cermet phase Ti C with high melting point,relatively negative Gibbs free energy,moderate density,high hardness,high modulus,excellent wear resistance and thermal stability is used to the joint reinforced phase,based on nickel high-temperature alloy Inconel 718 is a high-temperature high-strength wear-resistant high temperature alloy matrix composite material for the matrix,in order to meet the harsh service environment of turbine blades.In this paper,XRD,OM,SEM,EDS and other methods are used to analyze the phase composition of the powder raw materials and composite materials and the microstructure of the composite materials.The effect of mixed powder composition ratio and plasma melting deposition process parameters on the microstructure of composite materials was discussed;The average microhardness of the composite material was tested using a microhardness tester;the high temperature dry sliding friction and wear properties of the composite materials were tested using the SRV high temperature wear test machine.The composition and morphology of the wear surface of the composite material and the morphology of the three-dimensional wear scar were analyzed by SEM,EDS and three-dimensional white light interference surface topography,and the high temperature wear mechanism of the composite material was discussed.The results show that:the microstructure of the composite material prepared with the powder composition of Inconel 718,Cr powder and Si powder is mainly composed of Cr₃Si,Cr₁₃Ni₅Si₂ and?-?Ni,Fe?;the microstructure of the composite material prepared with the powder composition of Inconel 718,Cr powder and Si powder,Ti powder,nickel-coated graphite powder is mainly composed of primary Ti C,Cr₃Si,Cr₁₃Ni₅Si₂ and??Ni,Fe?solid solution.When the powder composition ratio is Inconel718-Cr50.4-Si9.6?wt.%?and Inconel 718-Cr58.8-Si11.2?wt.%?,the microstructure characteristics of the composite material are irregular flaky,fishbone and cross-petal shaped Cr₃Si reinforced phases are evenly distributed on Cr₁₃Ni₅Si₂/??Ni,Fe?eutectic.When the powder composition ratio is Inconel 718-Cr58.8-Si11.2-Ti8.3-Ni-coated graphite1.7?wt.%?,Inconel 718-Cr54.6-Si10.4-Ti12.5-Ni-coated graphite2.5?wt.%?and Inconel 718-Cr50.4-Si9.6-Ti16.7-nickel-coated graphite3.3?wt.%?,The microstruc ture of the composite material was observed in the form of particles,irregular clusters and snowflake-like precipitation of Ti C first,The precipitated Ti C particles are the nucleation core,and irregular flaky,fishbone and cross petal-shaped Cr₃Si are precipitated around them.Ti C and Cr₃Si are dispersed on the Cr₁₃Ni₅Si₂/??Ni,Fe?eutectic matrix.Compared with the plasma melting deposition Inconel 718,the average microhardness of the composite material is significantly improved.The average microhardness of the composite material of Inconel 718-Cr50.4-Si9.6?wt.%?,Inconel718-Cr58.8-Si11.2?wt.%?,Inconel 718-Cr58.8-Si11.2-Ti8.3-Ni-coated graphite1.7?wt.%?,Inconel 718-Cr54.6-Si10.4-Ti12.5-Ni-coated graphite2.5?wt.%?and Inconel718-Cr50.4-Si9.6-Ti16.7-nickel-coated graphite3.3?wt.%?is 2.40 times,2.55 times,2.82 times,2.97 times and 3.20 times of the comparison sample.Under the same high-temperature dry sliding wear condition test,the friction coefficient and wear loss weight of the five composite materials prepared with different powder composition ratios were significantly lower than those of plasma melting deposition Inconel 718,The composite material of the powder composition ratio of Inconel 718-Cr50.4-Si 9.6-Ti16.7-Ni-coated graphite3.3?wt.%?shows the lowest friction coefficient and the smallest weight loss;with the increase of Cr₃Si content in the composite material,the relative wear resistance of the composite material correspondingly improved;the wear mechanism of composite materials is lighter abrasive wear,oxidative wear and adhesive wear.Its good high-temperature wear resistance benefits from the high-temperature anti-wear backbone of high-temperature wear-resistant reinforced phase Cr₃Si and Ti C and Inconel 718 with excellent high-temperature toughness The bonding and support of the substrate.At the same time,the composite material has good high temperature oxidation resistance.