This claim is from https://www.totalmateria.com/page.aspx?ID=CheckArticle&site=kts&NM=122

Higher temperature is supposed to make deformation easy , right? then why is this trend happening as per claimed in that site?

Edit (4 May 2023):

ChatGPT replies to this

Steel inclusions containing FeO and (FeMn)O can exhibit anomalous thermal behavior because these oxides can undergo a phase transition at high temperatures.

At room temperature, FeO and (FeMn)O are typically in the wüstite phase, which has a cubic crystal structure and is relatively plastic. However, as the temperature is increased above 400°C, the oxides begin to undergo a phase transition to a more stable, hexagonal structure known as hematite. This phase transition causes the oxides to become less plastic, and they may even become brittle and prone to cracking.

The phase transition from wüstite to hematite is driven by changes in the crystal structure of the oxide as well as changes in the oxidation state of the iron. At high temperatures, the Fe2+ ions in wüstite can be oxidized to Fe3+, which is more stable in the hematite phase. This change in oxidation state, combined with the structural changes, causes the oxide to become less plastic and more brittle.

The anomalous thermal behavior of steel inclusions containing FeO and (FeMn)O can have important implications for the mechanical properties of the steel. For example, if the inclusions become brittle at high temperatures, they may be more prone to cracking and failure under stress. Therefore, it is important to understand the thermal behavior of steel inclusions in order to design and produce high-quality steel products.

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The reason for this unusual behavior lies in the crystal structure of wüstite. Wüstite has a defect spinel structure, which consists of oxygen ions arranged in a face-centered cubic lattice, with Fe2+ ions occupying some of the octahedral sites in the lattice. The presence of defects and vacancies in the crystal structure of wüstite creates a high degree of disorder and instability, which in turn allows the material to exhibit significant plasticity.

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It is also worth noting that the plasticity of wüstite is limited and decreases rapidly with increasing temperature. As the temperature increases, the defects in the crystal structure become more mobile and the material becomes less stable, which leads to a decrease in plasticity and an increase in brittleness.

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The plasticity of wüstite is due to the fact that the ... presence of defects and vacancies in the crystal structure of wüstite creates a large number of slip planes, which are regions where the crystal lattice can easily deform under applied stress. When a load is applied to the material, the defects allow the lattice to slip and slide along these planes, which allows the material to undergo plastic deformation.

It is true that the defects in wüstite can also create stress concentration points, which can contribute to fracture under certain conditions. However, the plasticity of wüstite is typically observed at room temperature and low stresses, where the defects do not create significant stress concentrations. At higher temperatures or under higher stresses, the defects can contribute to brittle behavior and fracture.

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But when I asked

defect amount is lower and dislocation is less mobile at lower temperature, both are supposed to cause more, not less stress concentration. Why the case is opposite for wustite?

Its response was like

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In addition, the specific defects present in the wüstite crystal structure, such as iron vacancies and oxygen interstitials, may also contribute to the material's unique behavior at low temperatures. These defects can interact in complex ways with the dislocations and other defects present in the material, leading to a more ductile response than might be expected based on crystal symmetry and defect density alone.

It is worth noting that the behavior of wüstite under stress is still an active area of research, and there is still much to be learned about the factors that contribute to its plasticity at low temperatures. Nonetheless, the presence of numerous slip planes and the complex interaction of defects and dislocations in the crystal structure are likely to be important factors in this behavior.

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CAN ANY HUMAN EXPER HELP HERE, VALIDATING AND EXPLAINING THESE CLAIMS AND LOGICS BEHIND???

ChatGPT suggests these papers. Can you please help me find one, especially the first one?