{"id":238093,"date":"2021-04-28T22:39:37","date_gmt":"2021-04-28T19:39:37","guid":{"rendered":"https:\/\/en.buradabiliyorum.com\/scientists-see-chemical-short-range-order-in-medium-entropy-alloy\/"},"modified":"2021-04-28T22:39:37","modified_gmt":"2021-04-28T19:39:37","slug":"scientists-see-chemical-short-range-order-in-medium-entropy-alloy","status":"publish","type":"post","link":"https:\/\/buradabiliyorum.com\/en\/scientists-see-chemical-short-range-order-in-medium-entropy-alloy\/","title":{"rendered":"#Scientists see chemical short-range order in medium-entropy alloy"},"content":{"rendered":"

“#Scientists see chemical short-range order in medium-entropy alloy<\/strong>”<\/p>\n

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Chinese scientists have made direct observations of face-centered cubic VCoNi (medium)-entropy alloys (MEA) and for the first time proposed a convincing identification of subnanoscale chemical short-range order (CSRO). This achievement undisputedly resolves the pressing question of if, what and why CSRO exists, and how to explicitly identify CSRO.<\/p>\n


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This work, published in Nature<\/i> on April 29, was conducted by Prof. Wu Xiaolei from the Institute of Mechanics of the Chinese Academy of Science<\/a>s (CAS) in collaboration with Prof. Ma En’s team from Xi’an Jiaotong University and Prof. Zhu Jing’s team from Tsinghua University.<\/p>\n

Multi-principal element alloys\u2014also known as high (medium)-entropy alloys (HEAs\/MEAs)\u2014are a hot and frontier topic in multidisciplinary fields. In these HEAs\/MEAs, enthalpic interactions among constituent elements may induce various degrees of local chemical order (LCO), of which CSRO is arguably the most difficult to decipher.<\/p>\n

“CSRO is the crucial cut-in point for understanding the unique mechanical and physical behaviors of these HEAs\/MEAs. However, a monumental challenge lies in how to see CSROs. Seeing is believing,” said Prof. Wu Xiaolei, leader of the research team.<\/p>\n

“The identification of CSROs demands not only irrefutable diffraction evidence, but more importantly, also intricate chemical information on subnanometer-length scale regarding the different preferences of constituent species for occupying certain lattice planes\/sites in the first and second nearest-neighbor atomic shell(s). Such concrete evidence of CSRO has been sorely missing thus far,” said Prof. Ma.<\/p>\n

In this study, the researchers used a complete suite of tools and methods to analyze correlations and justify their origin, in order to avoid missing links or interference from artifacts.<\/p>\n

These tools unequivocally nailed down the CSRO, including its spatial extent, atomic packing configuration and preferential lattice occupancy by chemical species.<\/p>\n

Modeling of CSRO order parameters and correlations reveals that the CSROs originate from the nearest-neighbor preference for unlike (V-Co and V-Ni) pairs and avoidance of V-V pairs.<\/p>\n

The researchers also used atomic strain mapp<\/a>ing to demonstrate the dislocation interactions enhanced by the CSROs. This sheds light on their effects on plasticity mechanisms and mechanical properties upon deformation.<\/p>\n

“This work is a significant jump on the CSRO, providing for the community systematic and clear-cut experiments with direct evidence that resolves the debate\/uncertainty (or even controversy) left from previous work,” said Ma.<\/p>\n

“Local chemical order develops as an intrinsic feature in HEAs and MEAs. This offers a new knob to turn, i.e., we have an opportunity to tune the degree of CSRO to tailor the mechanical and physical properties of these new materials,” said Wu.<\/p>\n\n

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Scientists investigate 3-D-printed high-entropy alloys\n <\/p><\/div>\n

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\n More information:<\/strong>
\n Direct observation of chemical short-range order in a medium-entropy alloy, Nature<\/i> (2021). DOI: 10.1038\/s41586-021-03428-z<\/a><\/p><\/div>\n
\n Provided by
\n Chinese Academy of Sciences
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Citation<\/strong>:
\n Scientists see chemical short-range order in medium-entropy alloy (2021, April 28)
\n retrieved 28 April 2021
\n from https:\/\/phys.org\/news<\/a>\/2021-04-scientists-chemical-short-range-medium-entropy-alloy.html<\/p>\n

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