Microstructures
by George Langford, Sc.D., Massachusetts Institute of Technology, Cambridge, MA, 1966
Copyright©2005 by George Langford
Non Ferrous Alloys - Lesson 3 - Seventh specimen
Beryllium copper at 200X
 This is the same material as you just saw in the previous specimen, but now its hardness is Rockwell C39 after being treated as before and then aged for three hours at 315C.  What microstructural changes have accompanied this increase in hardness ?  This photomicrograph was taken at 200X as before and with the same etchant.
Beryllium copper at 1000X
 Here the magnification is 1000X, using oblique illumination.  Study the microstructure of this and of the preceding specimen before proceeding.












Note the discontinuous precipitation (at the alpha grain boundaries) and that the alpha has recrystallized (as the result of the strains of the alpha to alpha plus gamma-2 reaction).  Precipitation of gamma-2 involves a coherent interface and change in shape, which together cause strain markings to form in the etched microstructure.  Go on to 8.