[–] ACatIsFineToo ago
I can't really give a personal background without doxing myself, and it's the internet so I could easily be lying. But yes, it's a subject I have some knowledge about, though not my direct field. It's not at all like a freight train, it's an extremely small extremely fast moving particle. It can cause fission in some cases, of the single atom it hits. This would cause a substitution in the lattice, as well as often entrained helium remaining. It can also cause that atom to displace, causing a dislocation in the crystalline matrix. Neutron bombardment does not cause materials to disintegrate.
I'm trying to find good sources that aren't behind a paywall. This one is older and long - the relevant part starts around page 100 of the PDF. Libgen with the search term "neutron embrittlement" should bring up a wide range of papers that can be downloaded as PDFs.
https://inis.iaea.org/collection/NCLCollectionStore/_Public/07/222/7222068.pdf?r=1&r=1