Effect of nitrogen addition on sintering behavior of high-entropy alloy CrMnFeCoNi powder

Abstract

The effect of nitrogen addition on sintering behavior of high-entropy alloy CrMnFeCoNi powder has been investigated. CrMnFeCoNi alloy powders were nitrided to add nitrogen and then consolidated at three different temperatures. The microstructure of the nitrided CrMnFeCoNi alloy powders and sintered compacts was characterized using electron probe microanalysis (EPMA) system. In the compact sintered at 800 °C, a high-nitrogen-content region formed a continuous network structure around the low-nitrogen-content substrate. The hardness of the sintered compacts with nitrogen was higher than that of the compacts without nitrogen. The high-nitrogen-content region expanded into the substrate region. The Vickers hardness of the sintered compacts increased with an increase of sintering temperature up to 950 °C. Sintering at 1100 °C did not completely finish; the vacuum pressure in the sintering chamber rapidly increased because chromium nitride (CrN) decomposed. The results indicate that high-temperature sintering is ineffective for nitrogen-added CrMnFeCoNi alloy powder.