Abstract
Undercooling behavior and the structures of specimens solidified from undercooled melts of iron-phosphorus alloys containing up to 15%P have been investigated. A series of specimens having up to 3%P were readily undercooled by as much as approximately two tenths of the melting point. Further increasing phosphorus content up to 10.5% led to difficulties in undercooling and melts with more than 6%P normally solidified with almost no undercooling. In alloys containing more than 10.5%P of eutectic composition, undercooling was very marked again. Primary α did not undercool but undercoolings of primary Fe3P and Fe2P were very marked. Maximum degrees of primary Fe3P and Fe2P obtained in Fe-12.6%P alloy specimens were 280 and 132 degree, respectively. And those of stable α+Fe3P and metastable α+Fe2P eutectic obtained in Fe-10.5%P alloy specimens were 105 and 41 degree, respectively. The two eutectic structures changed from rod-like to anomalous eutectic structure by increasing undercooling. A great portion of α+Fe2P eutectic solidified in metastable system changed to stable α+Fe3P eutectic during solidification and cooling.
