Editorial for the Special Issue on the Occasion of Reinhard Pippan's 70th Birthday: Celebrating a Legacy of Innovation and Excellence in Material Science

On the occasion of Reinhard Pippan's 70th birthday, it is our profound honor to dedicate this special issue to a personality whose contributions have significantly advanced our understanding of material science. Reinhard Pippan, retired vice director and group leader at the Erich Schmid Institute, has devoted his career to exploring the mechanical properties of metals, alloys, and composites. His work spans the realms of plastic deformation, fatigue and fracture, as well as micro- and nanomechanics, with a strong focus on severe plastic deformation (SPD), novel nanostructured materials that can be synthesized by this, as well as uncovering their sometimes rather unexpected deformation and failure mechanisms.

Reinhard's journey in academia began with his education in physics at the Technical University Graz, culminating in a PhD from the Montanuniversität Leoben in 1982 under the supervision of Prof. H.P. Stüwe. His career has been predominantly associated with the Erich Schmid Institute (ESI) of Materials Science of the Austrian Academy of Sciences, where his research has flourished. Reinhard has been instrumental in introducing discrete dislocation mechanics to fracture and fatigue, leading to a deeper understanding of fatigue crack propagation and fracture processes. For the first 20 years of his career, this remained his main focus and led to significant impacts in these fields.

Driven by the idea that nanostructured materials should possess outstanding fracture and fatigue properties, Reinhard entered the field of severe plastic deformation (SPD) with the intention to synthesize such materials at ESI. Even though in the early days several SPD-techniques, such as equal channel angular pressing (ECAP), were already available at ESI, he early recognized the advantages of high pressure torsion for basic research work, rooted in the simplicity of the process and the extensive accessible parameter space. At the beginning, his main interest targeted the microstructural processes leading to ultrafine and nanograined structures, the limits of grain refinement and the underlying structure property relationships. His further advancements in the HPT-technology have created pathways to synthesize novel materials, for example super-saturated solid solutions, placing his SPD group at the forefront of this rapidly evolving field. Additionally, Reinhard placed great efforts in the upscaling of the process and made first steps into industrial applications of the HPT-technique.

Due to the limited material quantities available by SPD deformation and the need to better understand the uncommon mechanical properties of ultrafine-grained and nanostructured materials, the scope of Reinhard's research in the last twenty years extended into the micro- and nanomechanics domain, where his pioneering visions in micromechanical testing have set new standards. This encompasses for example the discrete dislocation based deformation of confined sample volumes and most notably the field of miniaturized fracture mechanics, where his vast knowledge in conventional fracture experiments and analysis laid out the foundation for transferring these experimental procedures to micron scales. In some cases, it took us years to finally realize ideas and experimental concepts that Reinhard had quickly sketched on an old machine punch card, his favorite notepad.

This special issue is an attempt to feature a collection of manuscripts that echo the diversity and depth of Reinhard Pippan's research interests. Topics range from high-pressure torsion and nanocrystalline materials to advanced characterization techniques and the role of microstructural elements in fatigue and fracture. But before briefly addressing some details of the articles in this special issue, we would like to share some notable details of the jubilate:

Born on October 29, 1954, in Klagenfurt, Austria, Reinhard Pippan has led a distinguished career marked by numerous accolades, including the Erich Schmid Award of the Austrian Academy of Sciences, the Wöhler Medal of the European Structural Integrity Society and the Tammann Gedenkmünze of the German Society of Materials Science. His academic journey, from studying mechanical engineering at a technical high school in Klagenfurt, graduating in physics at the TU Graz in 1980, receiving his PhD in materials science at the Montanuniversität Leoben in 1982, to obtaining his habilitation in Solid State Physics at the Montanuniversität in 1991 and being promoted to Professor at the Montanuniversität Leoben in 2004, reflects a deep-rooted passion for understanding material behavior at fundamental levels.

Reinhard Pippan's tenure at the Erich Schmid Institute includes pivotal roles such as serving as long time vice director and twice interim director of the institute, navigating the institute well guided through difficult times. Further, he was head of the Christian Doppler laboratory for local analysis of deformation and fracture, and principal investigator of the ERC Advanced Grant USMS, the first (and still only) such prestigious grant that was granted to a scientist in Leoben. His work has garnered numerous significant research grants and produced over 600 publications, underscoring his prolific contributions to the field.

His scientific leadership is most clearly visible through the numerous invited and plenary lectures he has given at prestigious conferences across his research areas. Reinhard's dedication to securing research funding and his active participation in these projects underscores his ability to drive forward-thinking research and secure necessary resources to support groundbreaking studies. Furthermore, his success also enabled him to take on undergraduates, PhD students and post docs and send them with exciting novel results to conferences across the globe.

One of the most remarkable aspects of Reinhard's career is his mentorship of young researchers, which both editors had the privilege to experience firsthand. His research team at the Erich Schmid Institute comprised numerous young scientists, most often funded through third-party projects, that would benefit from his extensive experience and guidance, academically and privately, being it over a beer in the workshop, a glass of red wine at his home, in the face of a rock climbing route, or during a skiing tour. Reinhard has always been an inexhaustible resource of positive ideas and inspiration. At this point we cannot forget to mention his cooking and baking skills. While Reinhard's wife, Sigrid, would frequently master the former, together they are a congenial duo when it comes to making ‘Kärntner Kasnudeln’, no matter whether for a group of 4 or 40 hungry students. And while the distant Corona was a challenge for all of us, it actually benefited Reinhard's baking skills, and the photo contest with Otmar over their newest sweets became legendary. Fueled by this incredible combination of scientific guidance, hospitality and friendship, many of his former students and postdocs have gone on to assume leading positions in European industries, international research institutes, and top universities. This mentorship highlights Reinhard's dedication to fostering the next generation of scientists and his substantial role in shaping the future of material science.

The manuscripts in this special issue represents a wide array of topics that resonate with Reinhard Pippan's research themes, which we attempted to categorize into five areas, which is quite challenging due to their strong topical interrelation. These articles are contributed by invited experts in their field, and for simplicity we name in the following overview only the invited author but deeply thank the entire author-teams:

As we present this special issue, we extend our heartfelt congratulations to Reinhard Pippan. His scientific endeavors have not only enriched materials science in general and the lives of those he interacted with, but he also set a benchmark for future research and mentorship. Your legacy is one of relentless pursuit of knowledge, innovative thinking, and a commitment to scientific excellence, paired with humor and friendship. As we honor his 70th birthday, we also look forward to the continued advancements his personality will undoubtedly inspire in the years to come.

Happy 70th Birthday, Reinhard! May your journey of discovery and innovation continue to inspire and lead the way in materials science, rock climbing routes and best off-piste powder skiing slopes. This special issue can only address the former, where it stands as a testament to your enduring impact on the field and your unwavering dedication to advancing our understanding of the complex interplay between materials’ microstructures and their mechanical properties.

The manuscripts included herein not only celebrate your achievements, but also serve as a beacon for future research, reflecting the profound influence you have had on the scientific community. Your work has left an indelible mark, and we are privileged to honor you through this compilation of cutting-edge research.

With heartfelt best wishes on behalf of all your friends and colleagues,

Daniel & Toni

Editors:

Univ.-Prof. DI Dr.mont. Daniel Kiener

Professor for Micro- & Nanomechanics of Materials

Department Materials Science, Chair of Material Physics

Montanuniversität Leoben

[email protected]

DI Dr.mont. Anton Hohenwarter

Group leader: Deformation, Fracture & Fatigue

Department Materials Science, Chair of Material Physics

Montanuniversität Leoben

[email protected]