Memory alloy special for tunnel smoke exhaust fire damper and preparation method thereof

Abstract

The invention belongs to the technical field of memory alloy processing, and discloses a special memory alloy for a tunnel smoke exhaust fire damper and a preparation method thereof. Its components by weight percentage are: nickel 14.5%, palladium 35.2%, titanium 49.6%, and the rest is copper. The preparation process is as follows: mixing materials, compacting, and SHS synthesis. The preparation period of the method of the invention only needs several minutes to tens of minutes, and the obtained alloy has a phase transition temperature of 230°C to 250°C, and its fully recoverable strain can reach about 4%, which is suitable for the field of fire fighting in tunnels.

Description

technical field [0001] The invention belongs to the technical field of memory alloy processing, and in particular relates to a special memory alloy for a tunnel smoke exhaust fire damper and a preparation method thereof. Background technique [0002] Shape memory alloy is a new type of functional material with shape memory effect and superelasticity, and is widely used in various fields. NiTi-based shape memory alloys have great development value in application prospects due to their excellent corrosion resistance and memory effect. In order to broaden the application range of NiTi alloys, other elements are usually added to obtain excellent properties. Adding Pd element to the NiTi memory alloy can make the alloy phase transition temperature in the range of 200°C-500°C, and this alloy is suitable for use in high temperature environment. The addition of Cu element narrows the phase transition hysteresis temperature, makes the martensitic phase transition temperature more s...

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Problems solved by technology

[0006] The traditional preparation method has some common disadvantages, that is, the equipment used is large, the cost is high, and the production cycle is long, which hinders the further popularization and application of NiTi shape memory alloy in a certain sense; because the melting and casting method uses block raw materials, the composition is difficult to control accurately , easy to produce segregation, affect the processing and performance of the material, it is often necessary to improve the performance of the ingot through multiple smelting and high-temperature homogenization treatment; the powder will inevitably be polluted during the preparation process of the powder metallurgy method, resulting in the oxidation of the sintered billet High content, poor processing plasticity, and in the sintering process, the sintering temperature is generally higher than 1215K to produce a more uniform NiTi alloy, but the temperature is too high to ensure the integrity of the compact shape

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