A process for producing a radiation resistant nanocrystalline material having a polycrystalline microstructure from a starting material selected from metals and metal alloys. The process including depositing the starting material by physical vapor deposition onto a substrate that is maintained at a substrate temperature from about room temperature to about 850 C to produce the nanocrystalline material. The process may also include heating the nanocrystalline material to a temperature of from about 450 C to about 800 C at a rate of temperature increase of from about 2 C/minute to about 30 C/minute; and maintaining the nanocrystalline material at the temperature of from about 450 C to about 800 C for a period from about 5 minutes to about 35 minutes. The nanocrystalline materials produced by the above process are also described. The nanocrystalline materials produced by the process are resistant to radiation damage.