Study On Preparation,Microstructure And Properties Of The AlTiNiCuCo_x High Entropy Alloy

With the social development and progress,traditional alloy materials have not been able to meet the needs of the industry on the performance of metal materials.Because of its high hardness and strength,good wear resistance and corrosion resistance,High Entropy Alloys can be widely used for cutting tools,abrasive and so on.The purpose of this study is to explore a cost-effective wear-resistant materials.In this paper,a new High Entropy Alloy AlTiNiCuCox was prepared by vacuum melting method.The effect of Co clement content on the phase composition,microstructure and properties of the as cast of AlTiNiCuCox High Entropy Alloy by metallographic microscope,scanning electron microscope,transmission electron microscope,X-rap diffraction,micro-hardness tester,friction wear testing machine and electrochemical workstation.The research on the microstructure of the alloy showed that the surface morphology and structure of the alloy were changed with the addition of Co element.XRD and SEM results show that,the alloy system is mainly composed of FCC+BCC mixed structure.Metallographic analysis showed that the amount of Co added,dendrites from large to dendritic transition,and then to the snow-like change,and then gradually converted into petal-like,and finally transformed into petals.SEM-EDS analysis showed that Cu element were enriched in the nondedrite,Al,Ti,Ni and Co were enriched in dendrites.TEM and TEM-EDS analysis showed that there was a small particle size of nano precipitated pase and dislocations in Cu-rich region.There were second phase and twins in the dendrites,and the second phase is different,and the second phase and matrix are common.Performance test result show that with increase of Co content,hardness value increases first and then decreases,the average micro-hardness of Co1.0 alloy is the highest,reached to 668.8 HV.The coefficient of friction of the overall alloy system was between 0.36～0.53,and the wear rate was 0.0008～0.0016 g.Corrosion resistance properties of AlTiNiCuCox was the best in alkali solution,among in three different corrosion conditions.Corrosion resistance properties of AlTiNiCuCo1.0 was the best.The results show that the AlTiNiCuCox High Entropy Alloy is mainly composed of simple FCC and BCC structure Rich Cu phases of FCC structure in ID.The matrix of in the DR with NiTi and TiCo phases of BCC structure.The secozhind pase of the inter-dendrite with AlCu2Ti,AlNi2Ti,AlCo2Ti,and CuNi phases of FCC structure.AlTiNiCuCox High Entropy Alloy,which is caused by the high mixing entropy of the system,the change of Co content and the phase structure and phase type.