Leora Dresselhaus-Marais | Faculty Spotlight

Leora Dresselhaus-Marais

Assistant Professor
Materials Science and Engineering

"My group at Stanford works on developing microscopes that allow us to “see” the basic science we need to overcome critical scientific challenges required to make manufacturing more sustainable."

What led you to the engineering field?

I did not start out in engineering – I started as a chemist, and over the course of my career within fundamental science transitioned to engineering so that I could find ways to make my science have the impact I wanted on society.

I received my Bachelor of Science in chemistry from the University of Pennsylvania, and obtained my Master’s in inorganic chemistry from the same institution. I then received my Ph.D in physical chemistry from MIT, where I learned how to develop optical techniques that could watch how extreme conditions drive chemistry and material failure. That inspired me to do a postdoc developing techniques to understand even more deeply how the structure of the lattice deforms inside crystals. As a Lawrence Fellow in the Physics Division at Lawrence Livermore National Laboratory, I developed the time-resolved version of the new technique Dark-Field X-ray Microscopy, which has allowed me to watch dislocations move inside metals in real-time (from seconds to femtoseconds!). Towards the end of my postdoc, as I saw the California wildfires raging around me and I watched industry moving slowly to update the carbon-intensive infrastructures we rely on today, I realized I wanted to find ways for my science and new techniques to have an impact on societal problems I cared about around me. This has led my journey to engineering, where my group now develops measurement techniques and models that we use to help enable new opportunities to decarbonize industrial processes.

What led you to Stanford and your current role?

I see Stanford as a nexus of fundamental science and impact on society. The culture in the Stanford engineering ecosystem has a strong balance of cutting-edge fundamental science, while also deeply diving into the applications at a broad level. This blossoms from our collaborative culture, spanning physics and chemistry, engineering disciplines, and important fields like techno-economics that help us to understand which questions we need to focus our research on to be able to impart specific societal changes.

As a measurement technique developer, I have always been drawn to Stanford and SLAC because of their leadership in that field. The Linac Coherent Light Source (LCLS) opened in the first year of my PhD – producing the world’s brightest and fastest-resolving X-rays ever possible! Scientists at SLAC and Stanford were watching the atoms move at their representative length and time scales, breaking barriers across many fields. I started to get involved in this science towards the end of my PhD and focused my postdoc on using those X-ray lasers to create microscopes that could watch the defects inside macroscopic metals to be able to see how materials break.

When I applied for faculty jobs, I realized that Stanford was bigger than just the leadership in photon science I had seen at SLAC. I saw the rich research culture, collaborative spirit, and new directions in sustainability, and I was hooked!

Please describe any of your current research you would like highlighted and describe its importance, and/or any research you hope to accomplish in the future.

My group at Stanford works on developing microscopes that allow us to “see” the basic science we need to overcome critical scientific challenges required to make manufacturing more sustainable. We largely focus on metallurgy, where millenia of blacksmithing and extraction technology have established refined techniques that can be difficult to change, even when they have significant emissions. The research in my group looks across the whole supply-chain of metallurgy: from extraction of source materials from their host rock materials, to understanding the performance of metals in their intended applications, and ultimately how to 3D print metals to manufacture intricate parts specialized to specific technologies.  

Some of my newest work coming out has been exploring some of the “big industry” metallurgy with a new twist. Steel is one of the most prevalent and important metals in the modern world, but its production today accounts for 8% of all global CO2 production, and the industry continues to grow today! When we look at where in the steelmaking sector the CO2 is produced, we find that half of those emissions come from one step – converting the iron ores we mine from the ground into molten iron metal that goes into our steel. This process – called “ironmaking” – has been developed for over 2000 years using coal, and is one of the most efficient and high-throughput technologies on the planet today. To be able to decarbonize steel production, we need to find ways to remove emissions from ironmaking. This includes developing new technologies, and finding ways to de-risk those new approaches so that companies will invest the necessary ~$1,000,000,000 required to build new emissions-free plants. The most promising emissions-free ironmaking approach today replaces coal with hydrogen gas – producing water instead of CO2. While this seems like an easy fix, the changes to the reaction and reactor designs required to make this reaction scale from grams in a laboratory to Gigatons on a reactor result in sticking that cause reactors to clog and need costly shutdowns and maintenance.

My group’s work has shown that hydrogen causes even the smallest nano-sized particles inside these >10-meter wide furnaces to stick into “whiskers” that clog the reactors. More recently, my students looked at the pores that form inside macroscopic ore pellets and used nanoscale 3D maps from our X-ray tomography measurements to model the orders of magnitude changes in the flow of reactive gasses through the reactors. Our work demonstrates how these subtle changes in the solid-state reaction can cause dramatic changes that can lead to reactor failures, or can amplify reaction rates by 5x! We are now extending this approach to find ways to predict how to reduce risk in designing feedstocks for these reactors.

Beyond our work on steelmaking, we have also developed new techniques to watch the dynamics of imperfections (defects) deep inside mm-thick crystalline samples. From studying dislocations to enable more systematic design of alloys, to studying phonons and heat in diamond to understand thermal management and functional properties, we have many exciting new projects that will have exciting results coming over the next year. And we have some new results showing different classes of defects inside metals as we 3D print them with other new microscopes we are creating. I encourage you all to stay tuned! 

What advice do you have for aspiring scientist researchers in the field?

The best advice that comes to mind is “always stay curious”. I urge my students to always ask questions. It can become easy for a scientist researcher to assume they know concepts or have answers because they have jargon to explain things. We often forget to ask the most fundamental questions about our assumptions because we assume things and forget to look back to see if those assumptions are still valid. A question may seem stupid, but there are so many uncertainties in the field also underneath a lot of jargon that may sound impressive, but often can also be hiding lack of knowledge or incomplete analysis underneath.