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What is widman statten structure?
Answer:
Primary Widman statten ferrite either directly grows from the austenite grain surfaces, whereas secondary Widmanst¨atten ferrite develops from any allotriomorphic ferrite that may be present in the microstructure.
Widmanst¨atten ferrite can form at temperatures close to the Ae3 temperature and hence can occur at very low driving forces; the under cooling needed amounts to a free energy change of only 50 J mol. This is much less than required to sustain diffusion less transformation. Because Widmanst¨atten ferrite forms at low under cooling (and above the T0 temperatures),
It is thermodynamically required that the carbon is redistributed during growth.
Widmanst¨atten ferrite can form at temperatures close to the Ae3 temperature and hence can occur at very low driving forces; the under cooling needed amounts to a free energy change of only 50 J mol. This is much less than required to sustain diffusion less transformation. Because Widmanst¨atten ferrite forms at low under cooling (and above the T0 temperatures),
It is thermodynamically required that the carbon is redistributed during growth.
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