A new publication in Acta Materialia investigates the possibility to partially substitute Cobalt with entropic alloys, focusing on the relative stabilities of the fcc and hcp structures.
Cobalt-base alloys are important for high temperature applications due to their possibility to form duplex fcc + hcp structures and their low stacking fault energy. However, there is an interest in substituting cobalt for economical, ethical and health reasons.
Both the thermodynamic and kinetic calculations in this publication were performed with Thermo-Calc software and the Diffusion module (DICTRA) together with the thermodynamic database TCHEA and the kinetic database MOBNI. Thermo-Calc was used to predict the phase fractions of fcc and hcp which were compared with experimental results. In the article, it is stated that the calculated thermodynamic values correlate relatively well with the experimental values. The authors concluded that designing duplex fcc + hcp Co-based alloys with computational tools is feasible.
Type 410 steels are typically welded by using consumables with matching composition. However, this type of steel has shown to have poor weldability which is related to formation of hard and brittle martensite in the weld zone, hydrogen-included cracking or retention of δ-ferrite which affects the toughness. One theory that explains the inconsistent toughness is that the wide composition ranges of the base metal results in wide variations of the A1-temperature. In the paper, this theory was investigated with the design of experiment (DoE) approach using Thermo-Calc to perform thermodynamic simulations. Thermo-Calc together with the TCFE8 database was used to predict A1 and A3 temperatures for various compositions.
efficiency of fossil-fired and nuclear power plants has caused raised operating
temperatures, which requires use of creep-resistant stainless steels in the
hottest regions of the plant. Grade 91 steels are used in the lower-temperature
heat recovery steam generators. To be able to join the high- and
low-temperature sections, dissimilar metal welds (DMWs) are necessary. The
problem with using DMWs is that it often results in extensive carbon diffusion
near the fusion boundary which creates brittle and large carbides that make the
strength-enhanced ferritic (CSEF) steels are today welded with Ni-based filler
metals to reduce the carbon diffusion between the dissimilar steels, which
reduces the formation of hard and soft zones that negatively affects the creep
strength. However, the high concentration of carbide forming elements in
Ni-based alloys still creates a driving force for carbon diffusion toward the
Thermo-Calc 2019b was released in June 2019 and introduces a new module for steel and slag processing, the Process Metallurgy Module, three new databases, a completely rewritten part of the calculation engine and more.
What is the biggest crisis humanity will face in the next 50 years? A lack of water? A lack of arable land? Perhaps the answer lies within the field of materials engineering with a lack of new materials? The last option may seem a surprising choice, but if you’ve dedicated your life to the study of materials science, you understand the critical role materials play in all facets of sustaining human life. This very question of materials and sustainability was explored last month at the Jubilee Seminar: Material is evolution – Materials, society, industry and sustainability held in Stockholm, Sweden, on May 15, 2019 in celebration of the Year of Materials.
The QS World University Rankings by Subject were announced for 2019, and once again, Thermo-Calc is used by a majority of the top 100 universities that specialise in materials science, with 72 of the top 100 schools using our software and databases. Thermo-Calc Software have long supported universities and we are proud to see that so many top universities are choosing to use our software in their materials science programs. Continue reading →
Thermo-Calc Software recently published a new comprehensive tutorial which teaches about the role of diffusion in materials and how the Diffusion module (DICTRA) can be applied to materials design and processing, called The Role of Diffusion in Materials.
A basic exercise at the beginning of the tutorial walks users through how to assess whether there is any leakage from a tube at a power plant. The exercises get increasingly complex as the tutorial progresses.
Additive manufacturing of metals is transforming materials design and processing in ways unimaginable even 10 years ago, offering the freedom to produce complex parts without the restraints of traditional manufacturing.
However, Additive Manufacturing is a complex process and the mechanical properties of these materials and the parameters which control their reproducibility are not yet well understood. For example, additive processes are typically associated with rapid cooling rates and large thermal gradients. This can give rise to high levels of residual stress in the final part and local inhomogeneities in alloy composition during solidification. Also, the effect of multiple thermal cycles on material properties is sometimes unknown and typically does not result in the properties of a similar cast or wrought metal.
A lot of research is now being published in this area by members of our community using Thermo-Calc and we want to share some of this work with you. Below you will find a sampling of some of the work that is being done using Thermo-Calc and our add-on modules for diffusion and precipitation to research additive manufacturing of metals.Continue reading →
The launch of a three-year research project across three countries and involving over 10 leading experts will significantly advance the design of titanium aluminide (TiAl) alloys used in the manufacture of lightweight aircraft turbine engine components.
The ADVANCE project—Sophisticated experiments and optimisation to advance an existing CALPHAD database for next generation TiAl alloys—consists of an extensive and ambitious experimental program to generate detailed and accurate phase equilibrium data for a series of homogenous Ti-Al-X alloys of high purity, aiming to resolve existing experimental controversies and to determine missing data points of relevance, and ultimately support modelling activities consisting of assessing and re-optimising individual subsystems and the development of cutting-edge CALPHAD databases for TiAl alloys.
Representatives of the ADVANCE consortium, left to right: Hai-Lin Chen (TCSAB), Roman Sowa (MTU), Annett Seide (MTU), Svea Mayer (MUL), Martin Schloffer (MTU), Martin Palm (MPIE), Anders Engström (TCSAB), Florian Pyczak (HZG), Marcus Rackel (HZG), Roland Schmier (MTU). Missing from the photo: Frank Stein (MPIE), Yang Yang (TCSAB)