Abstract

This article investigates the microstructural features, phase composition, and electrophysical properties of Co₂TiAl intermetallic alloy produced by self-propagating high-temperature synthesis (SHS) in combination with pressing. For the first time, a practically single-phase alloy based on the Co₂TiAl Heusler compound with the weight content of at least 82% was produced using SHS; the synthesis products also contain TiCo_x intermetallic compounds of variable composition. The unit cell parameter of Co₂TiAl was a = 5.8433 ± 0.0002 Å. Metallographic analysis of the microstructure after SHS pressing demonstrated structure densification and decrease in porosity in comparison with samples produced by regular SHS without application of load to the combusted sample. The average microhardness of the synthesized alloy was H_μ = 5650 MPa, and the electrical resistance of the synthesized material at ambient temperature was 1.35 μΩ m. Variations of specific electrical resistance were studied in vacuum of 1.33 × 10^–3 Pa in the temperature range of 77–1300 K. At temperatures above 600 K, the electrical resistance as a function of temperature ρ(T) in Co₂TiAl alloy exhibits a decrease in slope; that is, for the given alloy, there exists the so-called effect of resistance saturation. The Curie point corresponding to transition from the magnetic to paramagnetic state was 133 K.

中文翻译：

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SHS压制产生的2 Co-Ti-Al合金的电物理性质

摘要

本文研究了自蔓延高温合成（SHS）与压制相结合制备的Co ₂ TiAl金属间合金的微观结构，相组成和电物理性能。首次使用SHS生产了基于Co ₂ TiAl Heusler化合物的，重量含量至少为82％的实用单相合金。合成产物还包含可变组成的TiCo _x金属间化合物。Co的晶胞参数₂的TiAl是一个= 5.8433±0.0002Å。与常规SHS产生的样品相比，在未施加压力的情况下，SHS压制后的显微组织的金相分析显示出结构致密化和孔隙率降低。合成的合金的平均硬度为ħ _μ = 5650兆帕，并在环境温度下将合成的材料的电阻为1.35μΩ米。在77-1300 K的温度范围内，在1.33×10 ^–3 Pa的真空中研究了比电阻的变化。在600 K以上的温度下，Co _2中电阻随温度ρ（T）的变化TiAl合金的斜率降低；也就是说，对于给定的合金，存在所谓的电阻饱和效应。对应于从磁态到顺磁态转变的居里点为133K。