When 10:30 AM - 11:30 AM Sep 17, 2021
Where 1670 Beyster
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Computational Designs of Advanced Alloys with Improved Mechanical Performances and Corrosion Resistance


Associate Professor Liang Qi

The increasing energy demands and environmental problems require the development of advanced alloys with improved mechanical performances and corrosion resistance. In this talk, I will give two detailed examples to address these two problems from my recent research progresses. First, refractory alloys with high strengths are critical components for many high-temperature applications. However, their manufacturing is largely impeded by their low ductility and formability. With electronic/atomistic structure descriptors and a simple bond-counting model, we developed regression models to accurately and efficiently predict the unstable stacking fault energy (γusf) and surface energy (γsurf) for refractory multicomponent alloys. Using the regression models, we performed a systematic screening of γusf, γsurf, and their ratio in the high-order multicomponent systems to search for alloy candidates that may have enhanced strength-ductile synergies. First-principles calculations and experimental results also confirmed search results. Second, a significant challenge for applications of lightweight metals and alloys (such as Mg and Al alloys) is their poor corrosion resistance under service conditions. Corrosion of Mg alloys can result from the coupling of anodic dissolution of Mg and cathodic reduction of water on impurities such as Fe-rich second-phase particles. Experiments show that small quantities of Arsenic (As) or Germanium (Ge) can inhibit Mg corrosion, possibly slowing the hydrogen evolution reaction (HER) as the cathodic reaction on Fe surfaces. We designed thermodynamic and HER criteria and used high-throughput first-principles computations to search a pool of 68 elements. Our computational results predict that As and Ge are the best two alloying elements according to their ability to reduce the HER rate, in qualitative accord with recent experiments.

 

Reference:

  1. Yong-Jie Hu, Aditya Sundar, Shigenobu Ogata, Liang Qi, Screening of generalized stacking fault energies, surface energies and intrinsic ductile potency of refractory multicomponent alloys, Acta Materialia, 210 (2021) 116800
  2. Mingfei Zhang, Louis G. Hector, Yang Guo, Ming Liu, Liang Qi, First-principles search for alloying elements that increase corrosion resistance of Mg with second-phase particles of transition metal impurities, Computational Materials Science, 165 (2019) 154-166,

 

Bio:

Liang Qi joined the Department of Materials Science and Engineering at University of Michigan as an Assistant Professor in Winter 2015 and was promoted to Associate Professor in Sep 2021. He studied Materials Science and Engineering at Tsinghua University in China and got his bachelor’s degree in 2003. He earned his master's degree in Department of Materials Science and Engineering at the Ohio State University in 2007 and his doctoral degree in materials science and engineering at University of Pennsylvania in 2009. From 2009 to 2012, he worked as a postdoctoral research fellow at UPenn and Massachusetts Institute of Technology. Between 2012 and 2014, he worked as an assistant project scientist at University of California, Berkeley. His research fields are investigations of the mechanical and chemical properties of materials by applying theoretical and computational tools, including first-principles calculations, atomistic simulations, multiscale modeling and machine learning. He received the NSF CAREER award in 2019 and 2021 TMS Materials Processing & Manufacturing Division (MPMD) Young Leaders Professional Development Award.