Obituary of Frank Reginald Nunes Nabarro

Frank Nabarro, Emeritus Professor of Physics at the University of the Witwatersrand, South Africa, passed away on July 20, 2006 at the age of 90, after a distinguished career spanning almost seven decades. He was best known for his pioneering contributions to the theory of crystal lattice dislocations and their role in plasticity and work hardening. There can be few major developments in this field that he did not in some way leave his imprint on. He wielded enormous influence through his highly regarded monograph “Theory of Crystal Dislocations”, his extensive editing activities, particularly on the encyclopedic series of books “Dislocations in Solids”, and his innumerable personal ties.

Nabarro grew up in the UK, and by the late 1930’s had obtained degrees in mathematics and physics from Oxford University. Initially guided by Neville Mott, he undertook calculations of the dependence of the flow stress of a crystal on solute atoms and precipitates, highlighting the role of the flexibility of the dislocations involved. With Herbert Fröhlich he investigated the orientation of nuclear spins in a metal. In 1940 he published four papers on these topics, and was launched on his research career. During World War II he worked for the British Army Operational Research Group, for which he was later awarded an MBE.

After the War he resumed his academic career at Bristol University and later Birmingham University, the latter conferring on him the degree of DSc in 1953. During this period he wrote a number of seminal papers which established his reputation. His research output continued unabated throughout his life, and he rose to a position of unrivalled leadership in his field. He contributed important ideas to many topics, including the elastic theory of dislocations (which forms the basis of his monograph), dislocation pileup, work and solution hardening, Harper-Dorn and diffusional creep, the Peierls-Nabarro stress (which he always referred to as the Peierls stress), the effect of elastic energy on the shape of precipitate particles, the interaction of sound waves with dislocations, and crystal whiskers. In recent years he turned his attention to creep resistant materials and rafting in superalloys which, with de Villiers, he surveyed in a monographHe has also published on quasicrystals, nematic liquid crystals, superconductivity, disclinations and biomaterials.

In 1953 Nabarro moved to South Africa to take up the position of Head of the Department of Physics at the University of the Witwatersrand. Within a few years he built up the department to significant strength in a number of areas. He served the University in various capacities, including a term as Deputy Vice Chancellor. During his tenure in that position he was responsible for drawing up the first academic plan of any South African University which prepared for the anticipated large influx of black students as the strictures of apartheid broke down.

He retired in 1984, but remained an active member of the University community, always generous with his time and wise counsel. Even as recently as May 2006 he chaired a meeting that brought together interested parties to discuss the desirability of establishing a local centre of excellence in biomaterials.

Nabarro had a significant input over many years in the development of physics and science as a whole in South Africa, through the active role he played in the SA Institute of Physics, the Royal Society of SA and Academy of Science of SA.

Nabarro’s energy and resilience were phenomenal, his intellectual vitality extraordinary. He never stopped being active in research, and currently has two papers in press, one with Shrivastava and Luyckx on “The size effect in micro-indentation”, and the other a thoughtful essay on “Creep in commercially pure metals”. He was editing Volumes 13 and 14 of “Dislocations in Solids” when he passed away. He traveled extensively, attending conferences and giving lectures wherever he went. Even as recently as May 2006, despite deteriorating health, he visited China and India, bringing to completion a research project with an Indian collaborator and giving a number of talks.

Nabarro held visiting positions at a number of universities in the USA, Canada, the UK, Germany, France, Israel and Switzerland. He was the recipient of numerous awards, including the Institute of Materials Platinum Medal and a number of honorary doctorates, and there were festschrifts in his honor. He was a Foreign Associate of the US Academy of Engineering, and a Fellow of the Royal Society of the UK.