Topic:

Technical seminar /Webinar on High-entropy Alloys – Progress and Prospects

Organizer：

Materials Division

Date, Time & Venue

17 January 2022 (Monday). Time: 6:30pm -8:00 pm, at Chan Yat Mei Sophie Room, 9/F of the HKIE Headquarters.

Speaker: Professor Chan Hung SHEK,

Professor, Department of Materials Science and Engineering,

Associate Dean (Education) College of Engineering, City University of Hong Kong

Professor Chan Hung SHEK received his BSc (Hons) in Engineering (Mechanical Engineering) and PhD from The University of Hong Kong, and joined City University of Hong Kong in 1994. His research interests are on the microstructure and properties of bulk amorphous alloys, nanocrystalline ceramic and other metallic alloys. He has co-authored over 210 research papers in international refereed journals, six book chapters, and was a co-inventor of one US patent and two PRC patents. He also conducts failure investigations for the industries.

Programme Highlights

Conventional engineering alloys, for instance, steels, aluminium alloys, titanium alloys, etc., are mostly consisting of a single principal element with alloying elements added in small atomic fractions to fine tune the properties. In recent years, a novel approach for designing new alloys was proposed. High Entropy Alloys, also known as multi-principal element alloys, are formed by mixing five or more elements in roughly equal atomic fractions. This approach opens up vast composition spaces for discovery of new engineering alloys with structures and properties not seen in conventional alloys. The studies of these alloys is one of the most vibrant and exciting research fields in metals and alloys in recent years. Brief introductions of the concepts behind these new families of alloys, their properties and possible applications will be given in this talk.

Registration & Enquiries

The talk would be carried out on both physical (20 seats) and zoom (100 seats) arrangement. Registration is required. Please fill the application before on 10 January 2022. Confirmation will be made through WhatsAPP and email. For physical, the maximum of participants is 10, for Zoom meeting, the participants would be limited to 100. For enquiry, please contact Ir CS Lam at 91527659. Attendance Certificate will be issued within 3 weeks after completion of the seminar. Applicants please fill the online registration form:

https://docs.google.com/forms/d/e/1FAIpQLSfPkgEeRY-B7gXk73h9GJHIUt4-sC8Jbgr7NOqjR8B5EqAzdA/viewform?vc=0&c=0&w=1&flr=0

The successful applicants will be confirmed through email.

By Ir LAM Chi sing

A webinar/technical seminar on High Entropy Alloys was conducted on 17 January 2022 at the HKIE Headquarters. Professor C. H. Shek introduced the basic concepts, properties and potential applications of high entropy alloys (HEA) to the audience. Conventional engineering alloys such as steel and aluminum alloys were developed by adding minor fractions of alloying elements to a base metallic element for fine-tuning the properties to meet the needs of applications. Take stainless steels as an example, chromium, nickel, etc. are added in order to achieve the combination of strength, ductility and corrosion resistance for structural applications in hostile environments. However, a new concept of alloy design, known as high entropy alloys or complex composition alloys, was introduced in 2004. It was proposed that new alloys may be formed by mixing at least five metallic elements in near-equal proportions. This approach opened up a huge composition space, which was not explored in the past, for the discovery of new alloys for various applications.

In the early years of the development of HEA, researchers focused on identifying alloy compositions giving single-phase solid solution structure, because those were expected to give high strength while retaining good ductility. The name ‘high entropy alloys’ follows from the fact that high mixing entropy of multiple components favours the solid solution structure. However, such restriction has been lifted in recent years and the development of new alloys, with the combinations of properties unattainable in conventional engineering alloys, accelerated. Compared with commercially available alloys, HEAs have application potentials in areas involving extremely hostile environments. Some HEAs exhibit increasing strength and ductility with decreasing temperature down to cryogenic temperatures due to their peculiar deformation mechanisms. Some other refractory HEAs outperform nickel-base superalloys at temperatures above 800°C and can be candidate materials for making turbine blades, or hot-working dies for steel with better performance and life. With better understanding of the composition-properties relationships, HEA may even be an economic and sustainable way of metal recycling by evading the need for refining a complex mixture of scrap metals.

Finally the webinar ended with question-and-answer session.

(344 words)

Group photo: Ir CS Lam presenting souvenir to Professor CH Shek from right to left