Special Interview with Prof. Yuntian Zhu
On January 27, 2025, the Editorial Office of Microstructures had the privilege of interviewing Prof. Zhu, a distinguished scholar and senior editorial board member of the journal, who recently spearheaded the organization of a special issue on heterostructured materials. During the interview, Prof. Zhu shared profound insights into his groundbreaking research on heterostructured materials, their future industrial applications, and the evolving trends in materials science. He also provided valuable advice for young researchers and discussed the essential qualities of high-quality academic journals.
Interviewee Biography
Professor Yuntian Zhu received his Ph.D. degree in Materials Science and Engineering from the University of Texas at Austin in 1994. He joined the City University of Hong Kong as a Chair Professor in 2020, before which he was a Distinguished Professor in North Carolina State University, where he worked from 2007 to 2020. He worked as a postdoc, staff member and team leader in Los Alamos National Laboratory from 1994 to 2007. His research in recent years has focused on the deformation mechanisms at dislocation level and mechanical behaviors of heterostructured materials, and nano/ultrafine-grained materials. He is an experimentalist with primary interest in fundamental aspects of materials science and also in designing materials with superior strength and ductility.
Below are some specific questions answered by Prof. Zhu in this interview:
Q1. Heterogeneous materials as an emerging concept of metal material microstructure design, you proposed the concept of heterogeneous materials, and successfully prepared a variety of forms of high-performance heterogeneous metal materials. What inspired your exploration in this field? What do you think of the application prospects of heterogeneous materials in the future industry?
A: This new field started from a set of the experimental data on commercially pure (CP) Ti obtained by Prof. Xiaolei Wu in the Institute of Metal Research, CAS. Xiaolei processed the Ti using asymmetric cold rolling to produce nanostructured Ti. Subsequently, a short annealing was conducted in which only 25% of the volume recrystallized to form dislocation free larger grains with sizes of several micrometers. As a result, a heterogeneous lamella structure (HLS) formed in which the soft recrystallized zones were embedded in the nanostructured hard zones.
The mechanical properties of the HLS Ti defy the materials science principles and our past understanding. Typically, there is a tradeoff between strength and ductility for metals and alloys, in which high strength usually leads to low ductility, because high strength requires higher strain hardening rate to maintain the same ductility. In practice, high strength usually leads to lower strain hardening rate, which results in the strength-ductility tradeoff. Surprisingly, the HLS Ti possess the high strength of the nanostructured Ti and even better ductility than the initial coarse-grained Ti, which was believed impossible.
The extra ordinary strength and ductility exhibited by the HLS Ti suggest that a previously unknown materials physics was at play, which we found was the hetero deformation induced (HDI) strengthening and HDI strain hardening. We later also found that this new principle can also be applied to a variety of heterostructures, and this initiated a new, quickly developing materials field.
The biggest advantage of heterostructured materials is that they can be produced at large scale at low cost using current state-of-art industrial facilities, which makes it easy for their commercialization. This especially important for the commercialization of a new type of materials.
Q2. Could you give us a brief introduction of your current scientific research work and share the latest scientific research achievements made by your research team?
A: We are currently on two fronts of the heterostructured materials. Since this is a new area, we still have many fundamental issues that are not well understood. We are currently using several advanced tools for this study, including in-situ TEM, in-situ SEM, and in-situ synchrotron/neutron. Secondly, we are also trying to develop super strong and tough metals and alloys including Ti, stainless steel, etc.
Q3. You have held key positions in many of the world's leading academic institutions, and have long been committed to advancing the research and application of heterostructured materials. What do you think of the current research trends in the field of heterostructured materials? What breakthroughs do you think will have a profound impact on materials science in the next five years?
A: In the next five years, it is expected that we will have better understanding of the fundamental sciences of the heterostructured materials as well as some commercial applications. This will dramatically affect the manufacturing industries, especially where high strength and light weight are critical, such as electrical cars, robots, and drones.
Q4. As a senior editor and editorial board member of several academic journals, how do you think high-quality journals should effectively control the academic quality of manuscripts? What criteria and processes do you feel are essential to ensure that published papers are highly innovative and research-worthy?
A: It is critical to have a fair review process. No editor/reviewer knows all of the papers submitted to a journal. It is very important to have experts in the related research topics to check on the paper. We often see some papers published in top journals have blatant and fundamental mistakes, which somehow passed the review process, because neither the editor nor the reviewers know the subject very well.
Q5. What advice would you give to young researchers and academics? As a tutor, what aspects of students' abilities do you focus more on?
A: This is a hard question. There is a high competition in the academic community that forces young scholars/researchers to chase the hot research topics so that they can publish papers quickly and in “high-impact” journals. I’d like to say that they should also consider what new science or engineering are in their research and the long-term impact of their work. In other words, after the field cool off a few years later, does their work still have any scientific/engineering value?
For my own students, I train them to be independent researchers. I don’t expect them to stay in the lab all time. Instead, I expect them to think more and do less. In other words, they should think it over before doing an experiment. I want them to become scientists, not high-level technicians.
Q6. As a senior editorial board member of the Journal of Microstructures, what are your prospects for the future development direction and positioning of the journal? Could you recommend some hot topics in the field of structural materials to us?
A: I think Microstructures is on the right tract. I’m impressed by the energy and dedication of its editors. New materials often possess novel miscrostructures. I believe that Microstructures will be associated with the frontiers of the materials reseach.
Editor: Tian Yao
Production Editor: Ting Xu
Respectfully Submitted by the Journal Editorial Office of Microstructures
