Subject：Statistical physics approaches to the complex Earth system

Speaker：A.P Liang Qi

Emcee：Prof. Yang Yang

Time：9:00am, 9th June. 2020

Place:  VooV meeting 342841476  code:093872 

Abstract： 

Body-centered cubic (bcc) refractorymulticomponent alloys are of great interest due to their remarkable strength athigh temperatures. Optimizing the chemical compositions of these alloys toachieve a combination of high strength and room-temperature ductility remainschallenging. We first analyzed the electronic structures of defects in BCCrefractory alloys. A general linear correlation can be found between twodescriptors of local electronic structures at defects in pure metals and thesolute-defect interaction energies in binary alloys of refractory metals withtransition-metal substitutional solutes. This linear correlation plus aresidual-corrected regression model provides quantitative and efficientpredictions on the solute-defect interactions in alloys. In addition, withthese local/global electronic descriptors and a simple bond-counting model, wedeveloped regression models to accurately and efficiently predict the unstablestacking fault energy (γusf) and surface energy (γsurf)for refractory multicomponent alloys. Using the regression models, we performeda systematic screening of γusf, γsurf, and their ratio inthe high-order multicomponent systems to search for alloy candidates that mayhave enhanced strength-ductile synergies. First-principles calculations andreported experimental results also confirmed search results.

Referencesfor the first talk:

1.Hu, YJ., Zhao, G., Zhang, B. et al. Localelectronic descriptors for solute-defect interactions in bcc refractory metals,Nature Communications, 10 (2019) 4484

2.Yong-Jie Hu, Aditya Sundar,Shigenobu Ogata, Liang Qi, Screening of generalized stacking fault energies,surface energies and intrinsic ductile potency of refractory multicomponentalloys, Acta Materialia, 210 (2021) 116800.