| Citation | Prof. Greenwood is widely known for his studies relating atomic mobility, particularly across and along interfaces, to microstructural changes, dimensional instability, and phase separation in materials subjected to stress, high temperature, irradiation and chemical forces.
His work laid the foundation for understanding the slow growth of precipitates in solids at high temperatures. He was the first to recognise that the reduction of surface energy by the shrinkage of small precipitates and the growth of larger ones in an assembly of precipitates with a distribution of sizes would lead to an increase in the mean diameter proportional to the cube root of the time. This insight has since been highly developed by Wagner and others to become one of the central features of modern understanding of the evolution of microstructure in the solid state. He also played a key role in establishing important features of the nucleation and growth of gas bubbles in irradiated metals and in recognising diffusion creep as a separate deformation mode of reactor alloys at high temperature.
Together with other pioneers at Harwell he helped place the new subject of nuclear metallurgy on a firm physical basis. This bore fruit when he moved to Berkeley Nuclear Laboratories in 1960 where he set up a group which soon became internationally recognized for fundamental work in physical metallurgy. He successfully bridged the gap between basic and applied work and this contributed to the achievement of significant economies in the generation of nuclear electricity. Since 1966 he has been involved in running the School of Materials at Sheffield University, where he was also Pro-Vice-Chancellor for the period 1979-83. |