先进材料疑固实验室 Nucleation Laboratory of Advanced Materials Solidification Only when T>,we can conclude a phase will nucleate before βphase. ⊕ In general 4T+4,and thus the a-B transition composition C is shifted with respect to Cper,it is given by C-Cpor ATS -ATE T T B mg -m △TR ⊕ m mf are the liquidus slope of a and B D1 Effective liquidus line △Tn 上浒充通大学 SHANGHAI JIAO TONG UNIVERSITYNucleation Only when > , we can conclude α phase will nucleate before β phase. In general , and thus the α→β transition composition Cn α→β is shifted with respect to Cl per, it is given by are the liquidus slope of α and β