抄録
The development of the microstructure arising from the phase decomposition in the materials has been inferred from the equilibrium phase diagram. However, the equilibrium phase diagram does not give any information on the process of phase transformation. In the present work, we newly propose a Time-Temperature-Composition diagram, which is named as a T-t-c system diagram. By using the system diagram the sequense of phase transformation and the microstructural development with progress of ageing can be comprehensively described.