OCAS has a long track record in alloy development. Over the past decade, the team further explored and optimised its possibilities in the field of tailored alloy making. More complex alloys, larger and homogeneous casts, further downstream processing such as rolling, annealing and advanced characterisation.
Exploring the processing of ever more complex alloys
Combinatorial screening of structural alloys
Back in 2011, as member of AccMet – an EU FP7 large-scale integrating collaborative project on the accelerated discovery of alloy formulations using combinatorial principles, OCAS developed a unique experimental high throughput flow methodology. This combinatorial tool not only enabled OCAS to make a significant number of structural alloys. it also provided the possibility to rapidly screen these formulations. This combined ability to take the right decisions and take them fast, is highly beneficial for our customers.
Successful application of screening methodology in steel development
OCAS’s methodologies for accelerated screening, processing and characterisation of metal alloys have successfully been used in the RFCS Lightough project focussing on advanced steel stypes. More recently, OCAS’s competenties in this field will also be used in the iNiTiAl project for screening a large number of generic alloys, in order to get a better understanding of the intermetallic precipitation strengthening. OCAS is coordinating this European RFCS iNiTiAl project.
Furthermore, OCAS was invited to give a presentation in the EERA workhop “Materials discovery and development“
Screening of compositionally complex alloys: paving the way for machine learning
The Forge consortium aims to develop a set of cost-effective highly protective coatings, based on novel Compositionally Complex Materials (CCMs) – both metal Alloys (CCAs) and Ceramics (CCCs) – to provide the required hardness, chemical stability and gas barrier properties for challenging applications. OCAS’s role in this project will be to perform a first screening of the CCA’s. In its post “Paving the way for high entropy alloy machine learning“, OCAS explains how pioneering unknown alloy processing at lab-scale makes it possbile to gather enough data to train and feed the model. CCAs can offer an infinite pool of new alloy combinations. Despite the huge number of available hardness values in literature for HEA (high entropy alloys) and CCA, the need for a fast way to provide experimental data remains, as it is the only way to support databases and machine learning. This is even more so in case of advanced properties.
Hardness values: in orange HV10, in grey HV5 and in blue Machine learning predictions (Click image to enlarge)
In the graph, all samples have their unique composition. The making of these samples requires experienced staff both for the preparation (selection of raw materials and crucible) as for the casting. Based on past experiences in alloy making, OCAS was able to synthesise this wide variety of needed sample compositions in record time.
Upscaling is key
Once its processability is proven, OCAS can upscale to homogeneous lab casts of up to 100 kg. The ingot can be further processed to dimensions suitable for advanced property testing towards in-use properties.
Thanks to their exceptional properties High Entropy Alloys (HEA) attract attention from industry. To successfully commercialise these alloys, upscaling is key. So far, research remained limited to small volume synthesis techniques. Recently, using its in-house vacuum induction melting OCAS successfully made a 100 kg homogeneous Cantor’s CoCrFeMnNi high entropy alloy cast.
Casting and beyond: OCAS goes to great lengths
OCAS has extensive experience in melting different base alloys ranging from very pure iron to stainless steel, non-ferro alloys and complex alloys:
- from 100 to about 1000 g by small scale vacuum induction technology, without risk of contamination and guaranteed homogeneity
- 30 to about 100 kg by large scale vacuum induction melting
- 1000 A vacuum arc melter for alloys containing elements with higher melting points
Mastering this methodology, OCAS further expanded its capabilities to process ever more complex alloys. Today, OCAS possesses pilot scale facilities for casting (from a few grams up to 100 kg), rolling and several heat treatments as well as a broad range of characterisation tools, both for mechanical properties as for standard microstructural characterisation.
“CCAs can offer an infinite pool of new alloy combinations. Despite the huge number of available hardness values in literature for HEA and CCA, the need for a fast way to provide experimental data remains, as it is the only way to support databases and machine learning.”
“Being able to produce a 100 kg homogeneous cast of high entropy alloys is a highly promising step towards industrialisation”