Metallurgical and Mechanical Properties of Laser Cladded AlFeCuCrCoNi-WC10 High Entropy Alloy Coating

Abstract

In spite of excellent corrosion resistance, good ductility and low cost of AISI 316 austenitic stainless steel, the low hardness and poor mechanical characteristic of material restricts its applicability in several industrial services. To improve the mechanical properties AlFeCuCrCoNi-WC10 high-entropy alloy coatings were deposited via laser cladding on austenitic stainless steel AISI 316 substrate. The influence of WC on phase constituents, microstructure, microhardness and elemental distribution were investigated using X-ray diffractometry, optical microscopy microhardness tester and FESEM-EDS (Energy Dispersive Spectroscopy), respectively. The XRD peaks revealed that as clad AlFeCuCrCoNi-WC10 multiple principal element alloy coating composed of BCC, FCC and W-rich phase. The cladding zone microstructure is mainly consisting of fine-grained non-directional and equiaxed crystals away from the base material and columnar grains near the base material. The energy dispersive spectroscopy indicated segregation of W and Cr in the interdendritic region. However, other elements of the multiple principal element alloy are observed to be uniformly distributed throughout the cladding. The microhardness of the AlFeCuCrCoNi-WC10 (670 Hv0.5) high entropy alloy coating was 4.5 times greater than that of substrate AISI-316.

Effect of Aging Treatment on Microstructure and Mechanical Properties of Al0.7CoCrFeNi High Entropy Alloy

“…Solid solutions with several elements due to high entropy tend to be stable at high temperatures. It is remarkable that these alloys have low diffusion rate, which causes the formation of nanometer precipitates, and severe lattice distortion due to the difference in atomic radii [1,2].…”