In addition to alloys 197 and 209, an additional

ternary alloy was prepared by arc melting rather than by

the RSR process. The composition of this ternary, alloy

#17, was chosen as being representative of a compromise

ternary composition between the composition of RSR 197 and

RSR 209 (Table 3.1). The Ta and W were, of course, not

present in the ternary alloy.

 Alloy 185, an alloy similar to RSR 209, was used for

only one experiment. Its composition is given in Table

3.1.


 3.2 Heat Treatments


 The canned RSR 197 and RSR 209 alloys were soaked at

1315 degrees C for four hours and extruded as bar at an

extrusion ratio of 43/1 at 1200 C. The extruded bars were

subjected to the various heat treatments described in

Figure 3.1. The heat treatments were conducted in a

vacuum furnace accurate to + 5 C. The times and

temperatures for these thermal treatments were chosen

based on the times and temperatures for aging binary Ni-Mo

alloys described in Chapter 2. The processing variables

are summarized in Figure 3.1.

 The arc melted sample and an RSR 185 sample were

encapsulated in evacuated and He backfilled quartz tubing

prior to thermal treatment. The arc melted samples were

wrapped in four nines pure Ni foil to prevent reaction