» This article is about tempering in metallurgy. For other uses of the word, see temper. Tempering is a heat treatment technique for metals and alloys. In steels, tempering is done to "toughen" the metal by transforming brittle martensite into bainite or a combination of ferrite and cementite. Precipitation hardened alloys, like many grades of aluminum and superalloys, are tempered to precipitate intermetallic particles which strengthen the metal. The brittle martensite becomes strong and ducti… (More on Tempering)