Study On Wear Resistance Of Eutectic High Entropy Alloy Based On Image Recognition Analysis

The wear and failure of metal materials due to sand-bearing water flow is easy to induce the great damage of hydraulic machinery’s passing parts.There are many sand-bearing flows in China,which seriously affect the efficiency and safe and stable operation of hydraulic machinery.Eutectic high entropy alloy(EHEA)is a new type of wear resistant metal material.However,there are few researches on its wear resistance and quantitative evaluation in the application environment of hydraulic machinery.In this paper,a jet wear test device was designed and made to effectively accelerate the material wear process.Accelerated wear tests were carried out on NiCoCrFeNb0.45 eutectic high-entropy alloy,04Cr13Ni5Mo stainless steel commonly used in hydraulic machinery and 45 medium carbon steel at different erosion angles,and the wear resistance of eutectic high-entropy alloy was compared and analyzed.And failure mechanism of wear rules in order to further explore NiCoCrFeNb0.45,in this paper,by using digital image processing technology,on the material wear image grayscale transformation,binarization and wavelet processing,combined with the fractal theory in modern mathematics,the extraction and analysis of abrasion morphology characteristic value of the image and form a kind of intelligent,reliable,used for characterization of a new method of metal material abrasion damage accumulation degree.The main results show that:(1)The wear loss weight of NiCoCrFeNb0.45 of eutectic high-entropy alloy is less than twice as much as that of the other two materials,showing excellent anti-erosion wear performance,with the wear amount reaching its maximum at 45°,showing the wear mechanism of high ductility materials.When the erosion Angle is small,the hardening layer on the surface of NiCoCrFeNb0.45 will form slowly.With the increase of erosion Angle,the vertical impact will be enhanced,and the hardening layer will form quickly.Therefore,the abrasion rate will change with time and finally become stable.(2)In the case of inclined impact,the wear mechanism of EHEA is the plowing and micro-cutting caused by the oblique impact of sand grains,and the cutting mechanism is dominant.With the increase of Angle,the mechanism of wear is the micro structure deformation caused by sand grains and the spalling of metal plates.When subjected to vertical impact,the macroscopic contour section of the specimen presents a"W" shape,which is due to the impact direction deflection of the sand grains due to the effect of back pressure.In cavitation test,the cavitation mechanism of EHEA is mainly deformation pits and fatigue cracks caused by instantaneous fracture impact of fluid hollow bubbles.(3)The gray value of the image is directly related to the degree of wear of the material.Through mathematical conversion,the three-dimensional abrasive topography is restored according to the two-dimensional abrasive image,and the statistical characteristics of the abrasive image based on gray transformation,such as energy value,entropy and standard deviation,are quantitatively related to the degree of wear of the material.(4)Image binarization can realize quantitative identification of the number of wear marks and wear area on the material surface.Meanwhile,wavelet decomposition of the wear image reflects different characteristics of wear in different directions.Wavelet coefficient of the extracted sub-image can further evaluate the degree of wear.Abrasion images have self-similarity in statistical sense,so they have fractal characteristics.It is found through program calculation that the fractal dimension increases with the increase of abrasion depth,which has a good evaluation effect on the degree of metal abrasion.