FRICTION IN HIGH-ENTROPY CrNiTiZrCu ALLOYS

Since the CrNiTiZrCu alloy, copper and aluminum are a system of three levels - nanolevel, mesolevel and bulk phase, we will consider each layer. The R(I) nanolayer is a nanostructure ranging in size from 1.1 to 1.7 nm. Reconstruction or relaxation occurs in the R(I) layer with metal and alloy atoms, which is associated with the rearrangement of the surface. The R(II) mesolayer is a mesostructure from 110 to 170 nm (< 1 μm) in size, extending approximately to R(II) ≈ 100 R(I), where the bulk phase begins. As the upper alloy moves along the surface of the lower one, a new surface of nanometer thickness is formed again. This means that friction makes an oscillatory motion. As soon as the speed exceeds the critical value, and the formation of a nanolayer does not occur, the friction begins to depend on the speed. Layers R(I), R(II) and the bulk phase have different values of internal friction, which is proportional to internal stresses. When the alloy starts to move from above, a turbulent fragment appears during friction. This is manifested in the microstructure found on the surface of the alloy. A similar structure is typical for Benard cells. It has been established that if the product R(I)•W(I)a for a moving CrNiTiZrCu alloy over a copper or aluminum surface is less than a similar product, then their difference is ~ 1/f. This can serve as another criterion for choosing an antifriction alloy or a coating from it.