SEMINAR:The Contribution of Physical Metallurgy and Solidification...

SEMINAR:The Contribution of Physical Metallurgy and Solidification...


Speaker: Syamak Hossein Nedjad, SAHAND University of Technology, Iran

Title: The Contribution of Physical Metallurgy and Solidification to Metals Additive Manufacturing

Date/Time: 9 November 2022 / 13:40 - 14:30 PM

Location: FENS G035 

Abstract:Processing->Microstructure->Properties->Performance” is a well-known chain in materials science. Microstructure control is a key element in the series especially for high-performance materials, known as “Physical Metallurgy” for metallic materials. This presentation is devoted to the physical metallurgy of advanced steels; some worked examples on aerospace and automotive steels are presented, including:

•           Discontinuous grain boundary precipitation in Fe-Ni-Mn maraging steels

•           TEM/HRTEM study of nanotwining in constrained NiMn precipitates

•           Advanced high strength steels for automotive applications

The second part introduces a journey to new world in collaboration with Prof. Mehmet Yildiz (Sabanci University): 3D-printing of metal parts, reputed as Metal additive manufacturing (MAM) because of the layer-by-layer addition of tiny metal droplets to realize 3D builds. MAM realizes intricate microstructure and property engineering. A considerable part of MAM concerns stainless, maraging and tool steels, exceeding more than 20,000 records in web of science. A brief introduction of MAM processes as well as selected contributions of physical metallurgy and solidification science to MAM steels will be presented. It is shown that extraordinary cooling rate plays the key role in microstructure development during solidification of tiny melt pool during MAM. See our recent publication:

Syamak Hossein Nedjad,Mehmet Yildiz, Abdollah Saboori, Solidification behaviour of austenitic stainless steels during welding and directed energy deposition,Science and Technology of Welding and Joining,

Considering experimental difficulties of temperature field measurement inside transient and very small melt pool and heavy cost of high throughput experimentation, we have started phase-field simulation of solidification process during MAM. Phase-field models enable simulation of elements redistribution and dendritic solidification, a complicated free-boundary pattern formation problem which has been the subject of experimental solidification researches under microgravity condition in space so far. The basic concept and formulation of phase-field simulation for solidification of pure metals will be presented this time, to be continued with advanced level on alloy solidification in near future!

Bio: Syamak Hossein Nedjad is a faculty member in Department of Materials Science and Engineering, Sahand University of Technology, Tabriz, Iran. He has worked on processing and physical metallurgy of advanced steels since 1997, mainly focusing on the maraging type and dual-phase steels. Syamak gives lectures on Vacuum Melting and Processing of Advanced Alloys, X-ray Metrology of Nanomaterials, Electron Diffraction in Transmission Electron Microscopy, Solidification and Phase Transformations, with special attention to the interface and grain boundary impacts in metallic nanomaterials. Since 2019, he has engaged with solidification problems in metal additive manufacturing. Effect of high cooling rates during solidification, theories of dendritic and rapid solidification, phase-field simulation of microstructure development during solidification is currently studied, with parallel experimental researches related to the effect of laser surface melting, resembling the 3D printing MAM processes, on the microstructure of stainless steels, and magnetostrictive alloys.