Author: santiagoc

NiHard-4 and high-Cr-Mo white cast irons are extensively used in mining and mineral processing applications. The microstructure and mechanical properties of these abrasion resistant materials are highly sensitive to the chemical composition and heat treatment conditions. A mineAlloy team led by researchers at University of Queensland (Maziar Jokari, Yahia Ali and Jeff Gates) has recently published a study on the abrasion performance of NiHard-4 and High-Cr-Mo, using their inner circumference abrasion testing (ICAT) equipment. The article emphasises the influence of Cr:C and Cr:Fe ratios on the hardness and fracture toughness of the eutectic carbides. The full text is available at https://doi.org/10.1016/j.wear.2021.204208

mineAlloy researchers at University of Queensland have recently published an article on the Effect of TiB₂ additions on the microstructure and mechanical properties of a hypereutectic high chromium cast iron. The research team used TiB₂ to reduce the average size and aspect ratio of primary carbides with the ultimate goal of improving the mechanical properties and wear resistance. The full article is available at https://doi.org/10.1007/s10853-021-06429-5

Prof Peter Hodgson delivered a workshop on “Writing papers with impact” to mineAlloy students and researchers. The workshop took place at Deakin Waurn Ponds campus and several researchers connected remotely over Zoom. The presentation covered all aspects of scientific publications, from identifying a suitable journal and audience, to writing a clear and compelling story. A recording of the session is available on demand for mineAlloy delegates and one-to-one sessions were arranged subsequently, upon request.

A delegation from Weir Minerals visited University of Queensland earlier this year to discuss the progress of their mineAlloy projects. The projects are dedicated to high chromium white cast irons and high manganese Hadfield steels and researchers at UQ have recently made a couple of breakthroughs, which resulted in the filing of two provisional patents.

In addition to this, Abhishek Jain and Arul Varman started their internships at Weir Minerals Australia in December 2020. Due to Covid-related restrictions, the internships will take place remotely, and most of the work will be undertaken at The University of Queensland until the situation normalises.

Abhishek Jain: “I would like to thank Weir Minerals Australia and the mineAlloy ITTC for arranging this internship and for giving me the opportunity to gain industrial experience. I particularly thank our colleagues at Weir Minerals for providing detailed information about their industrial processes and for their continuous support and guidance in this project.”

Prof Christopher Hutchinson, from Monash University, delivered a talk at the 2020 Alloy Design Workshop hosted by the Massachusetts Institute of Technology (MIT) on 4^th December 2020. The workshop had an impressive line-up, including: Prof Hugo Sandim (University of Sao Paulo), Prof Zhaoping Lu (University of Science and Technology Beijing), Prof Gregory Olson (MIT), Prof John Ågren (KTH), Prof Francisca Caballero (Spanish National Research Council), Prof Davesh Misra (University of Texas at El Paso), Prof John Speer (Colorado School of Mines), Prof Cem Tasan (MIT) and Prof Christopher Hutchinson (Monash University).

Prof Hutchinson’s talk, entitled Damage resistant microstructures generated from chemically patterned austenite was very well received by the international audience and led to some rich discussions in the Q&A session that followed. The workshop covered the most recent ideas to push the limits of metastability-engineering towards steels with superior damage resistance, and it was a great opportunity to showcase the excellent work conducted by Monash and mineAlloy researchers.

The mineAlloy training centre held its annual meeting on 24^th November 2020 in a rather unusual setting. Given the travel restrictions and the social distancing rules in effect at the time of the meeting, the attendees connected remotely, from their home office or from geographically dispersed meeting rooms, through a videoconferencing platform.

The event offered a cross section of the research activities of mineAlloy students and postdoctoral fellows and it also gave the attendees an opportunity to learn more about the resources and expertise available across the Centre. The meeting finished with a valuable discussion with the industry partners on the challenges and opportunities that became apparent during the year.

Thanks to the organising committee for the effort: Abhishek Jain, Chunkit Sit, Roshan Sasi, Alireza Vahid, Jiangting Wang and Arul Varman.

mineAlloy hosted the 2^nd Workshop on Computational Thermodynamics and Kinetics on Tuesday 24^th November 2020. The event was attended by more than 50 students and researchers from academia and industry. Dr Richard Ball represented ThermoCalc, who supported this event, and he provided a summary of the recent improvements in the software and the thermodynamic databases. Following this presentation, Dr Tiger Tang from Weir Minerals offered a few examples to illustrate how ThermoCalc is used in a commercial/industrial context. Finally, the workshop on computational thermodynamics and kinetics was delivered by Prof Christopher Hutchinson and Dr Yuxiang Wu from Monash University. The presenters covered a wide range of topics, including: thermodynamic equilibrium calculations and Scheil-Gulliver simulations using ThermoCalc, solidification, homogenisation and microsegregation simulations using DICTRA, as well as complex alloy composition and heat treatment optimisation using the ThermoCalc toolbox for MATLAB.

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 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.

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

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

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.