ABSTRACT
The first commercial dispersion-modified metal product, ductile tungsten, made its way into the marketplace near the tum of the century. Ductile tungsten was made by adding a thoria dispersion, and it is still a commercial product. Fink (1910) and Coolidge (1910) developed this alloy in the General Electric Laboratories and reported that "large quantities" of drawn wire containing about
0.7% thoria were produced and used as filaments in incandescent lamps (Fink, 1912). Early studies of the metallurgical nature of this new product were made by Jeffries (1918), who examined the retardation of grain growth by thoria in tungsten. It was also discovered that nonradioactive additions of Al, Si, and K to tungsten could produce the same grain shape stabilization and ductilizing functions as thoria (Pacz, 1922).
