Phase, Composition and Structure Changes of CoCrNi-Based Concentrated Alloys Resulting from High Temperature Oxidation

Abstract

In this work, CoCrNi, FeCoCrNi and CoCrFeMnNi concentrated alloys with a Y-Ti oxide particle dispersion were prepared by mechanical alloying and Spark Plasma Sintering. The alloy consists of an FCC Ni-based matrix with a Y-Ti oxide dispersion and additional phases of Cr23C6 and Cr2O3. The effect of Fe, Mn, and Y-Ti oxide particles on the formation of oxide scales and the composition of the adjacent CoCrNi and FeCoCrNi alloys was studied. It was found that alloys without Mn in their composition form a protective Cr2O3 scale. The Cr23C6 particles provide an alternative mechanism for balancing the chromium loss during the oxidation. Y and Ti from the oxide particles participate in the formation of the protective oxide scales. Fe promotes Y and especially Ti diffusion through the Cr2O3 scale, resulting in the formation of Ti-depleted regions in the alloy. The findings will serve for the further development of these new materials.

Characterization and Wear Behavior of CoCrNi Medium Entropy Alloy Coating on Al Alloy by Resistance Seam Processing

“…However, there was rarely report about CoCrNi MEA coating on Al alloy at present. The large difference in melting point between CoCrNi MEA (>1400°C) 16) and Al alloy (<660°C) makes it very difficult to prepare MEA coating on Al alloy. In our previous study, the RESP method was successfully applied in preparing the HEA-related coatings on Al and Mg alloys.…”

Significant Improvement the Mechanical Properties of CoCrNi Alloy by Tailoring a Dual FCC-Phase Structure

“…Composed of multi-principal elements, high-entropy alloys (HEAs) and medium-entropy alloys (MEAs) have attracted wide attention in the field of materials science and the engineering community. This is owing to their excellent comprehensive mechanical properties such as high tensile strength and high plasticity, excellent high-temperature strength [1][2][3]. Among various MEAs, the CoCrNi alloy which is composed of a single face-centred cubic (FCC) phase is particularly attractive, due to its exceptional properties at cryogenic and medium temperature range over other MEAs and conventional alloys [4].…”