The Microstructure And Properties Of High Entropy Alloy Ti_xFeCoCrWSi Coating Synthesised By Laser Cladding

High entropy alloy has attracted a lot of attention because of its unique design concept beyond the traditional and excellent properties, the concept of high entropy alloy has been proposed only a few decades, but it have been a great breakthrough,some high entropy alloy has been applied in industry. at present the block high entropy alloy is prepared by traditional casting method, however, the study of high entropy alloy coating is less.In order to attain excellent properties coating, high entropy alloy(HEA)TixFeCoCrWSi 、the matrix composite of SiFeCoCrTi+WC and Fe CoCrWSi+Y2O3coating are prepared on 45 steel by laser cladding. by means of OM、XRD、SEM、EDS 、 hardness tester 、 wear testing and electrochemical workstation, the microstructure、 phase、 microhardness、wear resistance and corrosion-resisting property are investigated.The experiment result show that the microstructure of the HEA TixFeCoCrWSi coating is dendrite, the amount of Ti(molar ratio x=0.5~1.5) can promote the grain refinement and the addition of Ti promotes the formation of BCC solid solution phase,when the content of Ti is 2 molar, the intermetallic compounds of coating reduce dramatically. furthermore, the EDS analysis show that the element of Cr and W are enriched in dendrites, the element of Fe 、Co and Ti segregate in the grain boundary. the average hardness of TixFeCoCrWSi alloy coating of entropy in500~800HV, With the increase of Ti content, the dilution rate of Fe in the matrix increase, which leading to the average of microhardness of coating decreasing. The average hardness of coating without Ti additive is 779.5HV0.2, the content of Ti is 2molar, the average microhardness of coating is 529.8HV0.2. The wear rate of high entropy alloy Ti0、Ti0.5、Ti1、Ti1.5、Ti2 coating are 0.7×E-5g/min、3.67×E-4g/min、2.23×E-4g/min、10.8×E-4g/min and 18.9×E-4g/min.the wear rate of high entropy alloy decrease with the increasing of Ti content,the abrasion resistance of coating decrease.electrochemical experiments show that the corrosion potential of coating without Ti additive is-526.914 mV, the corrosion current is 16.352 uA. the corrosion current is larger, the smaller the corrosion potential(more negative), poor corrosion resistance.the corrosion potential of high entropy alloy Ti2FeCoCrWSi(x=2)coating is-414.77 mV, the corrosion current is 2.067 uA. the high entropy alloy Ti2 FeCoCrWSi coating have the maximum corrosion potential Ecoor value(i.e. the maximum positive), while the lowest corrosion current Icoor, which shows that Ti2 FeCoCrWSi coating has excellent corrosion resistanceThe microstructure of the HEA SiFeCoCrTi coating is dendrite consisting of BCC phase and intermetallics. the coating form grain dendrite after adding WC particle, and large amounts of intermetallics are found in the coating, such as TiCo3、Co1.07Fe18.93. the dilution rate of substrate decrease and the properties of coating increase with adding WC particle. comparing to the HEA Si FeCoCrTi coating, the average hardness of the HEA SiFeCoCrTi coating increased by 23% and both of wear rate and friction coefficient decreased with adding WC, the wear-resisting property is improved obviously.The microstructure of the HEA FeCoCrWSi coating is consisting of BCC phase.the coating have excellent surface properties. the organize gradually refine and the average microhardness of the HEA coating reach a maximum value(659.6HV0.2) with adding 0.5% Y2O3, having outstanding wear-resisting property. meanwhile, both of wear rate and friction coefficient decreased with adding 0.5% Y2O3;however part of grain coarsening and the average microhardness of the HEA decreasing to a value589.5HV0.2 with adding 0.5% Y2O3, both of wear rate and friction coefficient enlarged with adding 1% Y2O3, the wear-resisting property is decreaced obviously.