Walter Rosenhain was a prominent German-born British metallurgist. He is noted for establishing the National Physical Laboratory (NPL) as one of the world's leading research labs in the field of metallurgy. He was a brilliant investigator and gained NPL the reputation of being one of the best-equipped research laboratories in the world.
Background
Walter Rosenhain was born on August 27, 1875, in Berlin, Germany. Rosenhain was the son of Moritz Rosenhain, a businessman. His mother, Friederike, was the daughter of Rabbi Benjamin Yosman Fink. The family immigrated to Australia in 1880 so that the son would not have to serve in the Prussian military.
Education
After attending Wesley College, Melbourne, and then Queen’s College, Melbourne University (1892–1897), where Rosenhain received the bachelor of civil engineering, Rosenhain went on to St John's College, Cambridge University as 1851 Exhibition scholar (1897–1899). He received a Doctor of Science degree from Melbourne in 1909. At Cambridge, Rosenhain studied under James Alfred Ewing, professor of mechanics. Initially, he was assigned to a project concerning the dynamics of steam jets. This problem proved uncongenial, and in November 1898 Rosenhain abandoned it to undertake an investigation, suggested by Ewing, that was to shape his career.
At St John's College, Cambridge (1899), he worked with (Sir) Alfred Ewing in the microscopic study of metal deformation, work which led to the discovery of slip-bands and spontaneous annealing of lead and other soft metals. In 1900 he became scientific adviser to the glass-makers, Chance Bros, at Smethwick, near Birmingham. He published several papers on optical glass and Glass Manufacture (1908). He described himself as “a tame scientist kept on the premises.” His engineering knowledge also found extensive application, however, and he retained a permanent interest in the technology of glass. His experiences led him to the study of refractory crucible materials of high purity. While continuing research in a private metallurgical laboratory Rosenhain first adopted George Beilby’s hypothesis that a thin metallic layer between slip lamellae is reduced to the amorphous state; this layer was taken to be very hard, like glass, thus explaining the mystery of work-hardening during plastic deformation. (Recovery of work-hardened metal was attributed to crystallization of the amorphous layer.)
Rosenhain soon extrapolated this notion to form the hypothesis that the boundaries between metal grains consist of thin (liquidlike) amorphous layers that, by analogy with work-hardened metal, he believed to be very hard at low temperatures but so soft at high temperatures as to favor intergranular rupture. Later he came to believe that the hardening of steel is due to the presence in quenched steel of amorphous layers that (by analogy with work-hardened metal) he took to be very hard at low temperatures. This complex of ideas, the “amorphous hypothesis,” became the scientific mainspring of Rosenhain’s standpoint and he devoted his exceptional powers as a controversialist to its defense. Modern techniques of X-ray diffraction and electron microscopy, used to establish the nature of hardened steel and the role of dislocations in plastic deformation, have proved the amorphous hypothesis wrong in all three of its aspects. But Rosenhain’s impassioned advocacy of the hypothesis did lead him to undertake valuable experimental work, particularly on plastic deformation.
A particularly informative account of the “β-iron controversy,” concerning the basic mechanism of the hardening of steel and including an account of Rosenhain’s early role in it, was published by Morris Cohen and James M. Harris. (Before conceiving the amorphous interpretation, Rosenhain was a firm defender of the fallacious β-iron theory of hardening.)
In 1906 Rosenhain was offered the post of superintendent of the recently established department of metallurgy and metallurgical chemistry at the National Physical Laboratory, Teddington. Rosenhain accepted the post, considering it a stepping-stone to better things, but he became absorbed by the work and remained there for twenty-five years. Under Rosenhain it became one of the world’s largest and most renowned metallurgical laboratories.
When Rosenhain arrived at Teddington, metallurgy (as the department’s quondam name illustrates) was virtually a branch of chemistry. Rosenhain steered metallurgy in the direction of physics, and through his influence, the new science of physical metallurgy emerged. His 1914 book Introduction to Physical Metallurgy was widely influential. This reorientation of the aims and methods of metallurgy was essential to rapid progress in the understanding of the structure and behavior of metals and alloys. Rosenhain, trained as an engineer, maintained close connections with the metallurgical industry; for him, the later separation of advanced metallurgical science and technology would have been unthinkable. His industrial outlook and connections enabled him to leave Teddington in 1931, before compulsory retirement from the civil service, to become a free-lance metallurgical consultant in London.
In 1923 Rosenhain toured American industrial and academic metallurgical installations, and his series of eleven articles in Engineer provides an expert impression of American metallurgy at that time.
At Teddington, Rosenhain participated especially in the development of instruments for physical metallurgical research, such as his gradient furnace and the plotting thermograph for registering thermal anomalies during the cooling of alloys. He also improved the metallurgical microscope and invented a recording dilatometer. He directed a long series of researches on the constitution of steels and on the constitution and age-hardening of aluminum alloys, which included the important aluminum-nickel-magnesium alloy known as “Y alloy.” Rosenhain established new standards of accuracy, paying particular attention to the purity of the constituent metals and - equally important - of the refractories used for making the melting crucibles. He also studied copper alloys and dental amalgams (the first instance of subzero metallography).
During a period when the conceptual basis of quantitative treatment of problems in physical metallurgy was not yet available, he contributed little of permanent importance as a theorist, except as a forceful controversialist who spurred others to fruitful attempts to prove him wrong.
Although not a practicing Jew Rosenhain resigned from several German scientific societies in protest against the treatment of Jews during the early years of the Hitler régime.
Membership
Walter Rosenhain was elected a fellow of the Royal Society in 1913 and he was also a member of the Optical Society of London.
Royal Society
,
United Kingdom
1913 - 1934
Personality
Rosenhain was a man of strong personality, clear in exposition and an inspiring team leader. He was noted for his remarkable command of foreign languages; he was able to pass from one language to another with the perfect facility and without halting or pause. He was a very fluent speaker in English, and his contributions to discussions at meetings of the Iron and Steel Institute, at which he was a regular attendant, were noteworthy for their interest and clarity.
Interests
foreign languages
Connections
In 1901, Walter Rosenhain married Louise, sister of Sir John Monash. He died of cancer in Surrey on 17 March 1934. His wife and two daughters survived him. Rosenhain was naturalized in England in 1914 but he visited Australia that year for the meeting of the British Association for the Advancement of Science. He retained links with Australia through his family and in particular through Monash, with whom he conducted a lengthy and intimate correspondence.