ACADEMIA lost one of its best with the recent death of Norman Petch. He will be remembered for having developed a number of widely used relationships to describe the strength and fracturing properties of engineering metals and alloys, particularly of steel materials. His work was of immense importance to the steel industry. He will be remembered for more reasons by those of us who were fortunate to have been associated with him and to be influenced by the gentle behaviour of a great intellect.
Petch's career provides a logical explanation of the scientific accomplishments for which he became world famous. He was a serious student and this led him scholastically from Glasgow to Cambridge, by way of London and Sheffield, not unlike similar routes traced by a number of fellow Scots and North countrymen. Under the tutelage of leading crystallographers at the Cavendish Laboratory, in Cambridge, Petch determined the positions of carbon atoms in the complicated crystal structure of iron carbide in steel. He also related the iron carbide carbon atom positions to those in the non-equilibrium structure of iron-carbon martensite and the solid solution structures of iron that occur at high temperature and in ambient practice - contributing to the establishment of a fundamental crystal structure basis for understanding the physical metallurgy of iron and steel materials.
Petch's X-ray results, from half a century ago, have stood up to the continuing scrutiny of these same fundamental structures with the present generation of advanced electron-microscope techniques. The quantitative aspect of these early crystal structure determinations in the Cavendish Laboratory very probably played an important role in influencing Petch to search for explicit relationships to connect the later measurements he made of polycrystal microstructures and the strength properties of steel and related materials.
Petch also began at Cambridge his life work into understanding the subject of the strength of materials, as described in the Yield, Flow and Fracture of Polycrystals book dedicated to him in 1982 on his imminent retirement as professor at Strathclyde University. His research into the subject gathered strength itself as he migrated north from the Royal Aircraft Establishment at Farnborough (during the Second World War), to Leeds in 1949, first as a reader then as Professor of Metallurgy in the Houldsworth School of Applied Science, where he aged considerably while supervising my postdoctoral studies; to the professorship in 1959 at Newcastle upon Tyne where he met his surviving wife, Marjorie, after devotion to his previous wife, Eileen, and enduring her loss with the help of his children, Alison and Judy; and then to Strathclyde University in his home city of Glasgow in 1973. He retired with Marjorie to renovate a family property, Finden Cottage, on the Black Isle - that we referred to as 'Finden College' for the congenial accommodation and continued research discussions pursued with a wee bit of Scotch malt whisky.
Petch's love for Scotland showed through during our family visits and in his correspondence on walks and tours done with Marjorie. During his retirement, he published a number of papers, which make up part of the book we were working on together that is nearly finished for publication by the Cambridge University Press. He was always pleased to see visitors at home where he continued with a number of activities done for the Royal Society. When Petch participated just a few years ago in an anniversary meeting at Cambridge dedicated to the accomplishments of his close colleague Sir Alan Cottrell, another colleague, DV Wilson, from Birmingham University, noted in a fine way the affection with which Petch too was held by his fellow scientists. Petch also received at the time the American Society for Metals (ASM) Gold Medal in Amsterdam at an ASM international meeting and, though worried about the American limit of two minutes allotted for his response to the award, found that it was time enough for him to say that he was confident of a mistake having been made in giving him the medal but nevertheless he had decided to keep the gift. Another colleague, WC Leslie, from US Steel and the University of Michigan, had commented earlier in the ASM nomination process that bestowing the award on Norman would add lustre to the medal.