Polymorphic transformations 上游充通大兽 SHANGHAI JIAO TONG UNIVERSITY Polymorphic transformations ■ In single component systems Liquid ■ Different crystal structures are stable over different 1538 -Fe temperature ranges 1394 ■ Eg.:fcc-and bcc-Fe y-Fe AO TONG 912 a-Fe 770 a-Fe A 0 Time min K.Chen 17K. Chen Polymorphic transformations  In single component systems  Different crystal structures are stable over different temperature ranges  Eg.: fcc- and bcc- Fe Polymorphic transformations 17 Liquid Time Temperature Non-magnetic Magnetic