Got this as a gift second handed and would like to sharpen it and make it usable again. The serrated top part started to just break off, so I am cautious about potential metal parts in my food. Any tips welcome, thanks.
Heating, quenching, and tempering is not a great idea if it can be avoided. It stresses the metal and can introduce new weaknesses.
And very few knives will have a softer core. That requires extra work on the knife makers part, and is rarely worth it. And there are signs you could look for during the repair and reprofiling. So a decent knife maker should be able to tell if it will be an issue.