| 摘要 |
PROBLEM TO BE SOLVED: To achieve a nozzle that is extremely strong against cracks, has extremely small melting and shape deformation of a channel surface, and requires less expensive material costs by forming the nozzle for generating a supersonic flow using a Cu alloy containing Cr and Zr. SOLUTION: W, Mo, Ta-W, Cu-W and Cu alloy containing Cr and Zr are selected as candidates for metal material with improved ductility and melting resistance properly for avoiding the crack of a channel surface and the generation of melting, a ductility test is extended, and the melting resistance property is drawn with a specific expression being standardized by a melt point Tm, a densityρ, a specific heat c, and a thermal conductivity k as an index, and a metal with a high index value is selected as a candidate. A nozzle was manufactured using the candidate material and a shock wind tunnel test was made. As a result, the nozzle made of W and Mo with small elongation results in a crack by one shock wave and hence does not play a role as the nozzle. Also, the nozzle made of Cu was deformed. On the other hand, the nozzle made of Cu alloy containing Cr and Zr had less amount of weight reduction and did not cause any crack even after testing at least for ten times, the deformation of the shape of the channel surface in a candidate material was small, and the Cu alloy containing Cr and Zr was found to be optimum.
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