open access

https://hdl.handle.net/2115/74671

Solidification Structure of Functionally Graded Hypereutectic Al-Ni Alloys Produced by Centrifugal Duplex Casting

日本語

solidification

2000-07

日本金属学会

Journal of the Japan Institute of Metals

64(7)

483-489

Solidification structures of Al-Ni and Al-Ni-Si alloys produced by Centrifugal Duplex Casting (CDC process) have been investigated. The CDC process is applicable to the production of a cast pipe of an aluminum alloy with an in situ composite layer containing fine intermetallic crystals. In this process, two molten metals, i.e. “the first melt” (aluminum or a hypoeutictic aluminum alloy) and “the second melt” (a hypereutectic or hyperperitectic aluminum-transition metal alloy with a higher liquidus temperature), are poured in sequence at a given interval into a roating mold of a centrifugal caster. Because the first melt acts as a coolant, the second melt is rapidly quenched to precipitate extremely fine primary crystals when they are mixed in the mold. When the first melt of an Al-5 mass%Ni alloy and the second melt of an Al-30 mass%Ni alloy were used, the composite layer in the CDC pipe consisted of the `“refined composite layer” with fine intermetallic particles and the “coarse composite layer” with relatively coarse particles. The coarse composite layer is subdivided into two sub-layers, i.e. the layer with accumulated flaky particles and that with freely grown particles. The refined composite layer was not formed when the first melt was aluminum whose melting point is higher than the liquidus temperature of the Al-5 mass%Ni alloy. On the other hand, large clusters with fine Al3Ni crystals were formed when the first melt was an Al-12 mass%Si alloy whose liquidus temperature is lower than the Al-Al3Ni eutectic temperature. However, these clusters did not form the refined composite layer but coexisted with flaky particles of Al3Ni.

学術雑誌論文

Version of Record

0021-4876

1880-6880

AN00062446