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High-entropy alloy
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<p>High-entropy alloys (HEAs) are <a href="/facts/Alloy/I7w7WQWR">alloys</a> that are formed by mixing equal or relatively large proportions of (usually) five or more <a href="/facts/Chemical_element/0jducgWD">elements</a>. Prior to the synthesis of these substances, typical <a href="/facts/Metal/PT8hNX6R">metal</a> alloys comprised one or two major components with smaller amounts of other elements. For example, additional elements can be added to <a href="/facts/Iron/QK1JYy8E">iron</a> to improve its properties, thereby creating an iron-based alloy, but typically in fairly low proportions, such as the proportions of <a href="/facts/Carbon/ukrgQexo">carbon</a>, <a href="/facts/Manganese/j9ELd1TL">manganese</a>, and others in various <a href="/facts/Steel/aN6qWo4H">steels</a>. Hence, high-entropy alloys are a novel class of materials. The term "high-entropy alloys" was coined by <a href="/facts/Taiwan/VcJoUD8w">Taiwanese</a> scientist Jien-Wei Yeh because the <a href="/facts/Entropy_of_mixing/zDdJNHTe">entropy increase of mixing</a> is substantially higher when there is a larger number of elements in the mix, and their proportions are more nearly equal. Some alternative names, such as multi-component alloys, compositionally complex alloys and multi-principal-element alloys are also suggested by other researchers. </p><p>These alloys are currently the focus of significant attention in <a href="/facts/Materials_science/N5HrXRYW">materials science</a> and engineering because they have potentially desirable properties. Furthermore, research indicates that some HEAs have considerably better <a href="/facts/Strength-to-weight_ratio/D3nbocax">strength-to-weight ratios</a>, with a higher degree of <a href="/facts/Fracture_mechanics/f9QogJzF">fracture resistance</a>, <a href="/facts/Tensile_strength/Cv2jPplR">tensile strength</a>, and <a href="/facts/Corrosion/lIC7H4we">corrosion</a> and <a href="/facts/Oxidation/Pyd5RVcj">oxidation</a> resistance than conventional alloys. Although HEAs have been studied since the 1980s, research substantially accelerated in the 2010s. </p>