Metallurgy, which traditionally had focused on industrial practice, was moving in the direction of becoming an engineering discipline based on scientific principles, Richards's texts on ore dressing and Hofman's texts on nonferrous metals and general metallurgy exemplified this trend in the area of metals production. The investigation of phase diagrams provided the basis for the solution of many typical metallurgical problems. Research on metallography and heat treating problems advanced physical metallurgy. Texts such as Rosenhain's "Introduction to the Study of Physical Metallurgy" (1914) and Jeffries and Archer's "Science of Metals" (1924) helped to establish the new subdiscipline. Fundamental scientific discoveries such as X-ray diffraction (von Laue, 1912) had contributed revolutionary experimental techniques and results.
At the same time, industrial practice progressed owing to various major developments: the adoption of the flotation process in ore dressing. the discovery of age hardening in aluminum alloys, and great advances in ferrous metallurgy, especially in heat treating and the use of alloy steels. Also, the first signs appeared that metals and materials generally were becoming recognized as major elements in engineering design and performance.