Characterization of high-entropy alloys: study of the addition of aluminum to the high entropy system HfMoTaTi+Al
Document typeBachelor thesis
Rights accessOpen Access
High Entropy Alloys (HEA) are alloy systems that are formed with five or more principal elements of alloy or have an entropy of mixture higher than 1.5R. Although at first it may seem like if it is extrapolated from binary and ternary diagrams these supposed high entropy alloys may generate very complex microstructures with multiple phases, segregations and intermetallic compounds, making them very difficult to analyze and understand, however, due to the thermodynamics involved in a system with multiple components, HEAs tend to have simple crystal structure like body-centered cubic (BCC) and face-centered cubic (FCC). Because of the first ideas that multiple elements alloys tend to have complicated microstructures and non-interesting properties, this field of study wasn’t explored until the year 2004 when Jian-Wei Yeh and Brian Candor started investigating them. After the first studies, showing to the world that these new alloys presented interesting properties, publications related to High Entropy Alloys started increasing worldwide as it can be seen in Figure 1. As the investigation effort related to HEAs is increasing, the more it is becoming clear that HEA systems exhibit excellent characteristics such as high strength and hardness, excellent wear resistance, high-temperature strength, good structural stability, good corrosion and oxidation resistance over conventional alloys.