The School of Mechanical and Materials Engineering Seminar Series, “Design and manufacturing of innovative high entropy alloys for extreme environment” Presented by Dr. Osman El Atwani

About the event

Design and manufacturing of innovative high entropy alloys for extreme environment

Presented by Dr. Osman El Atwani, Staff Scientist, Pacific Northwest National Lab (PNNL)

Abstract:

The performance of materials in extreme environments poses important fundamental questions about the behaviour of condensed matter under far-from-equilibrium conditions. These conditions create challenges in material design, synthesis and assessment. For example, the conditions expected in nuclear fusion reactors have triggered extensive research into the radiation tolerance of plasma facing and structural components, and their resistance to morphological changes and mechanical property degradation. Although extensive work has focused on identifying candidate materials and elucidate their response to extreme conditions, several outstanding questions of the multiscale processes which give rise to their radiation resistance remain unanswered.

Here, the challenges in designing an irradiation resistant plasma facing material are presented. As a proposed solution, via a combined experimental and simulation methodology, the design of a new nanocrystalline refractory high entropy alloy (RHEA) system is established. Compositions of this alloy, assessed under extreme environments and in situ electron-microscopy, revealed both high mechanical strength and thermal stability, grain refinement under heavy ion irradiation and outstanding irradiation resistance to dual-beam irradiation and helium implantation. Manufacturing of similar materials in bulk forms using 3D printing and arc-casting is presented and discussed. Outstanding questions in RHEA manufacturing and the need for further explorations, designs and advanced manufacturing and characterization techniques is elucidated.

Presenter Biography:

Dr. El Atwani is a staff scientist at PNNL. His research focuses on developing novel metallic materials including pure forms and alloys and investigating their performance under extreme irradiation and mechanical extremes. He performs research to study materials’ phenomena at different time and size scales using ex situ and in situ electron microscopy, mechanical and nanomechanical testing, and surface science techniques. He has been doing work on different nuclear materials such as nanocrystalline tungsten, high entropy alloys, BCC model materials, additive manufactured steels and advanced cladding materials. Dr. El Atwani has over 90 peer-reviewed journal publications, one granted patent, one patent undergoing licensing in related areas.