Relation between medium-range order and crystallization in Al-Ni based glass-former alloys

摘要

The structure evolutions of Al_(83)Ni_(10)Ce_5Si_2, Al_(83)Ni_(10)Ce_7, Al_(85)Ni_(10)Ce_5, Al_(87)Ni_7Nd_6 and Al_(87)Ni_5Co_2Nd_6 metallic glasses have been studied in detail. The studies establish a relation between the amount of medium range order (MRO) and crystallization mode. An increased amount of MRO suppresses the precipitation of primary fcc-Al and transforms the crystallization mode from a primary crystallization (Al_(87)Ni_7Nd_6) to a eutectic crystallization (Al_(87)Ni_5Co_2Nd_6); while a decreasing amount of MRO promotes the precipitation of primary fcc-Al and transforms the crystallization mode from a eutectic crystallization (Al_(83)Ni_(10)Ce_7 and Al_(85)Ni_(10)Ce_5) to a primary crystallization (Al_(83)Ni_(10)Ce_5Si_2).