Microstructures and Wear Resistance of Al_1.5CrFeNiTi_0.5and Al_1.5CrFeNiTi_0.5W_0.5 High Entropy Alloy Coatings Manufactured by Laser Cladding

Abstract

For the purpose of expanding the application scope of HEA coating manufactured on the surface modification of materials, in this work, the Al1.5CrFeNiTi0.5 and Al1.5CrFeNiTi0.5W0.5 HEA coatings were successfully manufactured using laser cladding method on SUS304. The microstructures and wear resistance of coatings are researched systematically. It is found that the W0 and W0.5 HEA coatings all exhibit the dendritic structure, which are constituted by BCC phases and Laves phases. With W element addition, the phase structures of W0.5 coating remain unchanged. W is dissolved in both two phases, but the solid solubility in Laves phase is higher compared to that in BCC phase. W0.5 coating with the highest microhardness of 848.34 HV, and the W0 coating with the microhardness of 811.45 HV, both of whose microhardness are four times more than that of SUS304 substrate. Among all samples, the W0.5 coating shows the optimal wear performance because of its larger content of hard second phase ( Laves phase).

Laves phases: a review of their functional and structural applications and an improved fundamental understanding of stability and properties

“…High-entropy alloys consisting of a tough disordered solid solution and a hard Laves phase (see Sect. 5.6.5) were tested as coatings on steels [550][551][552][553][554][555][556] and pure Ti [557]. Because of the high Laves phase contents, the coatings were reported in all cases to show excellent wear and oxidation behavior.…”

“…This behavior qualitatively agrees with a rule formulated by Guo et al [1076] for single-phase, cubic solid solution HEAs saying that for VEC \ 6.87 bcc is the stable structure while single-phase fcc solid solutions exist for VEC [ 8. Numerous examples for bcc ? Laves phase (see, for example, [554,557,1071,[1077][1078][1079][1080]) as well as fcc ? Laves phase (see, for example, [553,[1081][1082][1083][1084][1085][1086][1087][1088][1089][1090]) two-phase HEAs were reported in the literature.…”

“…Similar as for steels and other applied alloys, the occurrence of hard and brittle Laves phase precipitates was regarded as detrimental for a long time, see, for example, [1078]. However, today HEAs are intensively discussed as wear-and oxidation-resistant coatings for structural materials [1102], and the high hardness and excellent wear resistance of Laves phase have been recognized as very beneficial to improve the properties of such coatings [550][551][552][553][554][555][556][557].…”

High Entropy Alloys: The Materials of Future

“…According to the heating sources, cladding can be divided into laser cladding and plasma cladding. For example, alloy Al1.5CrFeNiTi0.5W0.5 was manufactured by Liang et al [47] using laser cladding on 304 stainless steel, and the HEA coating shows the optimum wear resistance. Figures 6 & 7 [48] show the differences between laser and plasma spray cladding processes respectively.…”