High temperature oxidation resistance of Al0.25CoCrFeNiMn and Al0.45CoCrFeNiSi0.45 high entropy alloys

Microstructural evolution of Al0.25CoCrFeNiCu and Al0.45CoCrFeNiSi0.45 high-entropy alloys during laser cladding

“…For the elements with a low difference in melting temperatures (Ni and Co), their enthalpies of mixing with other elements dominate the partitioning behavior. 31…”

“…HEAs ingots of the indicated compositions were first melted in an induction furnace according to the procedure detailed in our previous work. 30,31 Rectangular samples with a dimension of 10 × 10 × 10 mm were cut from the ingots, and then pressed to fabricate strips with a thickness of about 1 mm for laser cladding on the substrate. The 1 mm strip of Al 0.25 CoCrFeNiCu could be readily fabricated, however, Al 0.45 CoCrFeNiSi 0.45 alloy was too brittle to be pressed as strips, and it was crushed by the press to obtain powders with dimensions smaller than 1 mm for further deposition onto the substrate.…”

“…In this work, we investigated the laser cladding of Al x CoCrFeNiM (M = Cu, Si) HEAs on stainless steel. These compositions were selected from our previous studies on the high-temperature oxidation resistance of HEAs, 30,31 in which, we found that copper and silicon can effectively improve the high-temperature oxidation resistance of Al x CoCrFeNi HEAs. However, due to the high content of Co, Cr and Ni, the overall price of these HEAs is higher than conventional alloys.…”

High-Temperature Oxidation Behavior of AlxCoCrFeNiM (M = Cu, Ti, V) High-Entropy Alloys

“…Since the advent of HEAs, the interest in them has only been growing because HEAs, unlike conventional alloys with one or two basic components, feature a unique combination of properties: high strength and ductility [4,5], high mechanical properties at different temperatures [6], high fatigue resistance [7,8], high hardness and wear resistance [9][10][11][12][13][14], and high thermal stability [15,16]. Such properties of HEAs make them attractive as structural materials for operation under severe conditions (in gas turbines, jet and turbojet engines, etc.).…”

Effect of V and Ti on the Oxidation Resistance of WMoTaNb Refractory High-Entropy Alloy at High Temperatures

“…It is known that RHEAs, especially WMoTaNb alloys, suffer from poor oxidation resistance at elevated temperatures, which may be attributable to the evaporation of volatile oxides (MoO 3 , WO 3 and V 2 O 5 ) and the scale fractures caused by the high Pilling-Bedworth ratio (PBR) of Ta 2 O 5 (2.47) and Nb 2 O 5 (2.74) [11][12][13][14]. Researchers have undertaken a large number of studies on improving the oxidation resistance of HEAs by alloying beneficial elements, such as Al, Ti, Cr and Si [15][16][17][18]. Gorr and Lo found that a CrTaO 4 -based oxide layer can provide long-term oxidation resistance for RHEAs at elevated temperatures [19,20].…”