The topic of creating the right NAEs touches my recent querries for optimizing Nickel embrittlement. There's lots of info available in the public and scientific domain on reducing embrittlement of Nickel, hinting at some of the main possible causes.
Some of those causes: - Copper - Nickel alloys, where oxidized copper clusters in nickel alloys can form H2O and Copper, where the local H2O can cause very high pressures that in their turn can cause cracks (and holes). My association with this is the use of the Cu-Ni-Mn alloys Celani used for his recent research. - Carbon to enforce Nickel alloys. Under pressure and elevated temperatures Hydrogen and Carbon can form pockets of Methane causing embrittlement. Looking to causes of embrittlement of pure Nickel there are not so many hints that I could find so far. I guess absorbtion and desorbtion at certain rates are the most common known causes to create Nickel embrittlement. Are there others known? Last thing I would like to mention is the remarking indication of Defkalion of modifying Nickel lattice from FCC to C4 or a Pm3m structure, Any clues on how they would do this?
