Effect Of WC/TI C On The Structure And Properties Of MoFeCrTiW High Entropy Alloy Coating Prepared By Laser Cladding

To abtain coating materials with excellent properties, the high- entropy alloys MoFeCrTiW(WC)×(X presents mass fraction,X=10%、20%、30%) and MoFeCrTiW(TiC)y(Y stands for mass fraction,Y=5%、10%、15%)was prepared on Q235 steel by laser. At the same time, By means of OM, XRD, SEM, EDS, hardness tester,friction tester and electrochemical workstation, the effect of WC and TiC on the microstructure and properties of the high- entropy alloy MoFeCrTiW coating were investigated.Experimental results show that the microstructure of the high-entropy alloys MoFeCrTiW coating is composed of dendrite, with increasement of WC, the fine cell crystal is formed. When the content of WC is 10%, the coarse cellular-dendrite structure is formed, and the phase is consisted of BCC solid solution and a number of intermetallic compound. The average hardness of coating is 508HV0.2. Compared with coating without adding WC, the microhardness and wear-resistanc of coating are decreased. When the content of WC is 20%, the microstructure of coating is mainlyfine cell crystal, and the phase is consisted of BCC solid solution and intermetallic compound. However, the content of intermetallic decreased dramatically, the microhardness of coating is 539.5HV0.2, and the friction coefficient reduces. the wear-resistance of coating is greatly improved. When the content of WC is up to 30%,the microstructure of coating is fine and dense dendrite, the element of Mo,Ti and W is concentrated in dendrite, the element of Fe and Cr tends to segregate in interdendrite, the amount of intermetallic compound such as TiCr and TiCr2 are decreased dramatically. And a few dispersed WC particles are found in coating. The average value of hardness of coating is 657HV0.2,the friction coefficient and weight loss of coating are decreased. The wear resistance of coating is greatly improved.Electrochemical experiments show that the corrosion current density of coating is increased, the corrosion potential and corrosion resistance are decreased.Experimental results show that the high-entropy alloys MoFeCrTiW coating with5%TiC is mainly composed of dendrite and equiaxed cell crystal, the average value of hardness of coating is 526.6HV0.2, the wear resistance of coating is decreased. TiC particle is distributed in coating with the increasement of content of TiC. The element of Mo,Ti and W is focused on dendrite, the element of Fe,Cr and C tends to segregate interdendrite. The microhardness and wear-resistance of coating are improved dramatically. The average value of hardness of coating is 655.85HV0.2. When the content of TiC is 10%, the microstructure of coating is mainly consisted of dendrite and cell crystal. The number of intermetallic compounds are decreased dramatically,the average value of hardness of coating is 505.73HV0.2, the microhardness and wear resistance are decreased. When the content of TiC is up to 15%, the fine dendrite is formed, compared with coating without adding TiC, the corrosion resistance of coating decreases.