Pioneering friction stir additive manufacturing of steels

Dr Ehsan Farabi has recently joined the mineAlloy team at Deakin University. Ehsan is a physical metallurgist with interest in developing processing-structure-property links for advanced structural materials, mainly steels and titanium alloys. He has expertise in state-of-the-art characterisation techniques, such as electron microscopy (SEM), electron backscattered and transmission diffraction (EBSD and TKD), focused-ion beam (FIB), transmission electron microscopy (TEM). Ehsan specialises in the analysis of complex microstructures, combining experimental results with physical and metallurgical principles. His research is focused on the development of new alloys for advanced manufacturing. This includes understanding and predicting material behaviour, phase transformations, and microstructure evolution during material processing. Ehsan’s current project involves a fundamental study of the process-structure-property relationship of advanced steels during friction stir additive manufacturing (FSAM).

Chun Kit completes project on direct laser deposition of WC/Co

Chun Kit Sit has submitted his Master’s thesis on Direct Laser Deposition (DLD) of WC/Co cermets as wear-resistant coatings. WC/Co cermets are composite materials composed of tungsten carbide (ceramic) in a cobalt binder (metallic). WC/Co cermets are especially hard and wear resistant but their traditional manufacturing processes are expensive.

Direct laser deposition (DLC) of WC/Co is an alternative route for the fabrication of wear-resistant surfaces and it also opens the possibility of repairing used components. This is a particularly interesting option since the wear resistant material can be placed where it is most required, while the bulk of the component can be made from cheaper or tougher materials.

This thesis reports the process optimisation of DLD of WC/17Co coatings on a low carbon mild steel substrate and examines the wear performance of the coatings in both low-stress (ASTM B65) and high-stress (ASTM B611) wear tests.

Refinement of primary carbides in hypereutectic high-chromium cast irons

mineAlloy researchers from University of Queensland and Weir Minerals have recently published a review paper on the refinement of primary carbides in hypereutectic high-chromium cast irons. High-chromium cast irons (HCCIs) are widely used in mining, minerals and cementation industries. The large volume fraction of coarse primary carbides (M7C3) imparts excellent wear resistance, but it also results in high cracking susceptibility and early failure of components, particularly under impact loading. The mechanical performance of HCCIs is correlated with the microstructure of the matrix, as well as the size, shape, volume fraction and distribution of primary carbides. This paper comprehensively reviews the currently available methods to modify the primary M7C3 carbides in various HCCIs and, ultimately, to optimise their mechanical properties for wear resistant applications.

Follow this link to the full paper: https://doi.org/10.1007/s10853-020-05260-8

Postdoc in Advanced Characterisation

Dr Jiangting Wang is a research fellow and FIB-SEM manager at the Institute for Frontier Materials, Deakin University. He is specialised in advanced material characterisation, such as scanning electron microscopy (SEM), electron backscattered diffraction (EBSD), focused-ion beam (FIB), transmission electron microscopy (TEM), and atom probe tomography (APT). His previous research focused on understanding the microstructure and mechanical behaviours of high-strength low-alloy (HSLA) steels, twinning-induced plasticity (TWIP) steels, and magnesium alloys, using advanced characterisation techniques.

He joined the mineAlloy team in February 2020, to investigate the nano-scale microstructures and fundamental strengthening mechanisms of mining alloys using EBSD, FIB, TEM, and APT techniques. His focus will be on the precipitation-hardened Hadfield steels, high chromium cast iron, and high-strength bainitic steels. He will also be involved in characterising additively manufactured mining alloys.

More details about his research areas and publications can be found in the following link.

http://www.deakin.edu.au/about-deakin/people/jiangting-wang

Running DEM simulations at the National Computational Infrastructure

The researchers of mineAlloy, Vadim Zolotarevskiy and Michael Pereira, have been recently granted with access to the National Computational Infrastructure (NCI). The NCI facility operates Gadi – the most powerful Australian supercomputer. Gadi, that was launched in the beginning of 2020 and already ranked as 24th in the TOP500 list of the global supercomputers, makes it possible to conduct fast computations that rely on high-end CPU as well as GPU performance with the latest available hardware. Such an opportunity addresses the challenges of mineAlloy especially in the field of Discrete Element Method modelling, where time-efficient yet accurate simulations of complex multi-particle systems are of the top priorities.

Design, modelling and characterisation of wear-resistant steels

Yuxiang Wu is currently a research fellow in the Department of Materials Science and Engineering at Monash University. His work involves quantitative studies of microstructure development with both experimental and modelling components. He received his PhD in Materials Science and Engineering from Monash University in 2019. In the mineAlloy training centre, Yuxiang will provide support on the design, modelling and characterisation of wear-resistant steels.

Confirmations and completion

Congratulations to George Galis for successfully completing his confirmation of candidature at University of Queensland earlier this month. In this way, George joins the cohort of mineAlloy students who completed their confirmation of candidature this year, including: Abhishek Jain at University of Queensland, and Vamshi Chennuri, Roshan Sasi and Eigor Petry at Deakin University. In addition, Guillaume Bruel was recently awarded a Masters degree from Deakin University for his work on ‘Precipitation hardening of Fe-Mn-C steels for wear resistance improvement’. We celebrate the hard work and success of our HDR students in such challenging times. Well done, guys!

Xin starts master’s at Deakin

Xin Zheng has started his Master of Engineering project with the mineAlloy team at Deakin University. The project will use DEM modelling to develop design principles for titanium carbide inserts embedded in the mantles of cone crushers.

Xin recently completed his Bachelor of Mechanical Engineering (Honours) degree. His thesis was titled “Computational fluid dynamic simulation of drainage cannula in veno-arterial ECMO applications”.

Xin also completed a three-month internship with the mineAlloy team in 2019. During his internship, Xin became familiar with the Rocky DEM software, while conducting fundamental studies of particle-surface impacts and the effect of modelling parameters on the outputs.

Rocky DEM workshop

LEAP Australia and ESSS delivered a workshop on Rocky DEM software to graduate students and postdoctoral researchers from the Institute for Frontier Materials and the School of Engineering at Deakin University.

The presenters, Marcus Reis and Leon White, had originally planned to visit Waurn Ponds, but they had to deliver the workshop over ZOOM instead, because of the recent COVID19 travel restrictions.

The workshop covered the capabilities of this DEM software package in a broad context, and the researchers discussed its particular use in wear applications. The presenters also introduced some of the new features included in forthcoming versions of Rocky, expected to be released later in 2020.

PhD students wanted

The mineAlloy team at Deakin University is accepting expressions of interest from PhD candidates to join the mineAlloy training centre and related projects. The research topics gravitate around wear resistant materials, additive manufacturing and repair technologies, as well as advanced modelling and testing techniques.

To find out more, please follow this link and send your CV and any related questions to mineAlloy-enquiries@deakin.edu.au

Pushing the boundaries of modelling methods

Alban de Vaucorbeil recently published some of his work using the Material Point Method (MPM) to simulate engineering problems involving large displacements, large deformation and contacts. The article appeared in Computer methods in applied mechanics and engineering earlier this year (https://doi.org/10.1016/j.cma.2019.112783).

This article follows the publication of another paper dedicated to the simulation of damage and fracture of ductile materials using the Smooth Particle Hydrodynamic (SPH) method (https://doi.org/10.1002/nme.6306) which was also part of Alban’s postdoctoral work with the mineAlloy team at Monash University.

Matt delivers workshop on deformation

Prof Matthew Barnett, from Deakin University, delivered a workshop on deformation of materials to an audience composed of students and researchers of the mineAlloy training centre and beyond. The deformation mechanisms of metallic materials have a significant effect on their mechanical properties and wear resistance. The workshop covered both fundamental and practical aspects of dislocation motion, strain and shear microstructures.