Something like that happens inside iron crystals when the metal is brought to a high temperature without being melted and is then cooled. If carbon is present when these changes occur, a hard alloy can become soft or a soft one hard.
हे बदल घडत असताना कार्बन देखील असल्यास कठीण मिश्रधातू मऊ होऊ शकतो किंवा मऊ असलेला मिश्रधातू कठीण होऊ शकतो.