Hi Dale
Your question is a little cryptic, but I believe you are looking for a repair method for the particular material you are referring to, using GTAW.
I am not sure what alloy you have, but is looks like it is close to a 904 type of material. The nominal composition of 904L is:
25% Ni
20% Cr
4.5% Mo
1% Cu
Not quite what you specified, but close.
This can be welded with a matching filler: AWS A5.9 ER385
Regarding the cracking, you need to establish the reason for cracking before being able to make a reliable repair. For instance, if you had stress corrosion cracking, a repair may be very difficult to impossible, depending on the level of contamination of the base metal.
Just keep in mind that this is a fully austenitic material, so cleanliness while working with it is imperative if you want to avoid hot cracking.
If I am misreading your question, then please ask again.
Regards
Niekie Jooste
Fabristruct Solutions