Structure of As-cast aluminum matrix composite containing Ni3AI-type intermetallic ribbons

An aluminum matrix composite containing rapidly solidified Ni₇₅Al₂₃B₁Zr₁ (at. pct) ribbons has been fabricated by casting at 700 °C, 715 °C, 730 °C, and 875 °C. Microstructural investigation has shown that the matrix contains particles with a composition between Al₃Ni and eutectic. The interfacial zones composed of several layers with different aluminum and nickel contents are observed around the ribbons. The sequence of layers from the ribbon outward in the specimens fabricated at 700 °C, 715 °C, and 730 °C is as follows: AINi → Al₃Ni₂ → the outer layer between Al₃Ni and eutectic. Composite specimens fabricated at 875 °C contain two types of interfacial zones: a single-layer AINi and a triple-layer zone. The first two layers in the triplelayer zone are exactly the same as their counterparts in the specimens fabricated at lower temperatures. The outer layer has a composition close to the Al₃Ni compound. The thickness of the AINi layer increases continuously with the increasing casting temperature. Within the experimental error, the thickness of the Al₃Ni₂ layer seems to be independent of casting temperature. The thickness of the outer layer in the specimens fabricated at 700 °C to 730 °C (Al₃Ni plus eutectic) increases with the casting temperature. However, the outer layer in the 875 °C specimen (Al₃Ni) is much thinner than the others.