When exposed for prolonged periods at intermediate temperatures, HAYNES® 25 alloy exhibits a loss of
room temperature ductility in much the same fashion as some other solid-solution-strengthened superalloys, such as HASTELLOY® X alloy or alloy 625. This behavior occurs as a consequence of the precipitation of deleterious phases. In the case of a 25 alloy, the phase in question is CO2W laves phase. HAYNES® 188 alloy is significantly better in this regard than 25 alloy; however, for applications where thermal stability is important, 230® alloy is an even better selection.
Room-Temperature Properties of Sheet After Thermal Exposure*
Exposure
Temperature
|
-
|
0.2% Offset
Yield Strength
|
Ultimate
Tensile Strength
|
Elongation
|
|
°F
|
°C
|
h
|
ksi
|
MPa
|
ksi
|
MPa
|
%
|
|
None
|
0
|
66.8
|
460
|
135.0
|
930
|
48.7
|
|
1200
|
650
|
500
|
70.3
|
485
|
123.6
|
850
|
39.2
|
|
1000
|
92.3
|
635
|
140.0
|
965
|
24.8
|
|
2500
|
95.1
|
655
|
130.7
|
900
|
12.0
|
|
1400
|
760
|
100
|
68.9
|
475
|
115.3
|
795
|
18.1
|
|
1600
|
870
|
100
|
72.1
|
495
|
113.6
|
785
|
9.1
|
|
500
|
77.3
|
535
|
126.1
|
870
|
3.5
|
|
1000
|
81.7
|
565
|
142.0
|
980
|
5.0
|
*Composite of multiple sheet lot tests