Novel Applications of High Entropy Alloys

*Engineering Steels and High Entropy-Alloys*

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**Chapter 10**

**Abstract**

**1. Introduction**

**1.1 Background**

**181**

Applications

*and Andrei Victor Sandu*

or after some heat treatments, are highlighted.

magnetism, and significant resistance to corrosion [5].

High Entropy Alloys for Medical

A wide variety of metallic biomaterials have been developed so far, including various types of alloys. However, there is a strong need in the medical field for new solutions in what concerns metallic biomaterials with superior biocompatibility and mechanical properties in order to meet future requirements, including the recently developed high entropy alloys (HEAs). This chapter presents some characteristics of high entropy biocompatible metallic alloys produced in an electric-arc remelting furnace in argon inert atmosphere. The effects of the chemical elements used, the microstructural features, and some mechanical characteristics, both in the cast state

**Keywords:** high entropy alloys, biocompatible, microstructure, microhardness

HEAs are defined as alloys comprising more than five main elements mixed in an equiatomic or near-equiatomic fraction [1–14]. Many HEAs have been reported to have: superior mechanical properties, such as ultrahigh fracture even at high temperatures, high hardness, toughness exceeding that of most pure metals and alloys, excellent comparable strength to that of structural ceramics and some metallic glasses, exceptional ductility, and fracture toughness at cryogenic temperatures [1, 3], and good physical properties, such as superconductivity, super-

By replacing one or several elements in the composition of high entropy alloys, properties that significantly differ from the initial ones can be obtained. Furthermore, the decrease or increase in the ratio of additional elements can generate different metallographic structures with significant influences on the properties of alloys [6–10]. While high-strength conventional alloys are based mainly on the controlled distribution of one or two high-hardness phases at most, in high entropy alloys, the exceptional properties are based on the quenching effect of the supersaturated solid solution and on the suppression of the intermetallic phases [1, 4–12]. The complex distribution of the various chemical elements within the crystalline network of high entropy alloys appears to be the main cause of their special characteristics when compared to the classical or bi-component alloys. Choosing the combination of chemical elements could allow to simultaneously cumulate superior mechanical properties

*Victor Geanta, Ionelia Voiculescu, Petrica Vizureanu*
