engleski

Continuously cast Cu-Al-Ni shape memory alloy - Properties in as-cast condition

In respect to the cost of constituents, Cu-Al-Ni alloys can be regarded as low-cost shape memory alloys. However, the processing is quite costly due to the brittleness of the ingots. Therefore it would be advantageous to produce semi- finished products directly from the melt via highly productive technique. A laboratory device for vertical continuous casting directly from the vacuum induction melting furnace was experimentally employed for continuous casting of the Cu-13 wt.% Al-4wt.% Ni shape memory alloy. A water-cooled copper crystalliser with a graphite insert was used to cast with diameter 16 mm strands. Diverse sets of casting parameters were tested, the average casting speeds being within the range from 250 mm min-1 to 625 mm min-1. The castability of the alloy using this technique was good. Strands were examined in the as-cast condition, and no cracks or other defects were discovered. Medium casting speeds resulted in good surface quality, and a fully martensitic microstructure was obtained even at the lowest average casting speed. The paper presents and discusses the surface quality, microstructures and mechanical properties.

shape memory alloy ; Cu-Al-Ni ; vertical continuous casting ; microstructure ; mechanical properties

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