THE STRUCTURE OF METALS 



By CECIL H. DESCH, D.Sc, Ph.D. 



The study of the structure of metals in relation to their physical 

 and mechanical properties is of quite recent origin. Apart 

 from a few isolated observations by Hooke and Reaumur, the 

 first to use the microscope in investigating metals was 

 H. C. Sorby, the brilliant Sheffield amateur who was a pioneer 

 in so many departments of research. The method of preparing 

 and examining metallic specimens devised by Sorby in 1864 is 

 in all essential respects the same as that in general use at the 

 present time, notwithstanding the many important improvements 

 of detail introduced by later workers. His unwearied patience 

 and skill in applying the microscope to the study of iron and 

 steel were attended with remarkable results ; nevertheless, his 

 work passed almost without notice and nearly twenty years 

 elapsed before any general attention was given to the subject. 

 Since that time, the advance of microscopical metallography has 

 been rapid and continuous, in regard both to the number of 

 workers and to the methods of investigation and interpretation. 

 The subject of metallography is not confined to the study of 

 metals and alloys by means of the microscope but includes 

 investigation by thermal, electrical, mechanical and other 

 methods into which it is not proposed to enter now. 1 Reference 

 must also be made to text-books for details of the technique of 

 preparing and examining sections, merely noticing that, owing 

 to their opacity, metals have always to be examined by reflected 

 light. The object of the present article is to describe some of 

 the more important conclusions already established concerning 

 the internal structure of the principal metals and alloys of 

 technical importance and the connexion between structure 

 and practical utility. Appreciation of the value of the 



1 See, for example, W. Guertler, Metallographie, 2 vols., now in course of 

 publication (Berlin : Gebr. Borntraeger), or C. H. Desch, Metallography (London : 

 Longmans, Green & Co., 1910). 



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