As far as I remember, yes, everything becomes brittle at low enough temperatures. This is due to the brittle-to-ductile transition (BDT - or sometimes referred to in reverse as DBT, ductile-to...). This transition is temperature dependent (amongst others). Can every composition actually reach low enough temperatures, or do some have a transition temperature below 0K, of this I'm not sure. One thing to keep in mind though, is that dense things become very hard to break, likea leg of lamb or a banana. A sufficiently frozen banana (liquid nitrogen) will break, but it requires a lot of force. Simply dropping it from a meter or two will not shatter it. It needs to be thrown or hit with something harder. Yes, I have tried this. The bigger it is, the more force it would require. I can shatter any boulder for you, but you may not have the size of hammer I would need ...