高强度零热膨胀复合材料的制备与性能研究

Preparation and Properties of Zero-Thermal-Expansion Composites

摘要: 零热膨胀材料在温度变化过程中表现出优异的尺寸稳定性，在精密仪器、光学系统等关键领域具有重要的应用价值。具有优异磁体积效应的Ho₂Fe₁₇合金是极具潜力的负热膨胀材料，与正热膨胀材料复合后可实现零热膨胀，但其固有的本征脆性大且零热膨胀温域较窄，严重限制了其工程化应用进程。为了解决此问题，本研究利用电弧熔炉法制备了不同Cu含量的Ho₂Fe₁₇/Cu复合材料，借助热膨胀仪、万能试验机、扫描电子显微镜、能谱分析仪及振动样品磁强计等仪器，系统研究了材料的热膨胀系数、抗压强度、微观结构及磁相变行为。研究表明，12 wt.% Cu掺杂的Ho₂Fe₁₇/Cu复合材料在120~352 K的温区内的热膨胀系数低至0.51 ppm/K，抗压强度高达0.98 GPa，在精密仪器等领域展现出良好的应用前景。

Abstract: Zero-thermal-expansion materials exhibit excellent dimensional stability during temperature changes and are of significant practical value in critical fields such as precision instruments and optical systems. The Ho₂Fe₁₇ alloy, which possesses an outstanding magnetic volume effect, is a highly promising negative-thermal-expansion material; when combined with a positive-thermal-expansion material, it can achieve zero thermal expansion. However, its inherent high brittleness and narrow zero-thermal-expansion temperature range severely limit its engineering applications. To address this issue, this study prepared Ho₂Fe₁₇/Cu composites with different Cu contents by arc melting. Using instruments such as a thermal expansion analyzer, universal testing machine, scanning electron microscope, energy dispersive spectrometer and vibrating sample magnetometer, the thermal expansion coefficient, compressive strength, microstructure and magnetic phase transition behaviour of the material were systematically investigated. The study indicates that the Ho₂Fe₁₇/Cu composite containing 12 wt.% Cu exhibits a thermal expansion coefficient as low as 0.51 ppm/K within the temperature range of 120~352 K, with a compressive strength as high as 0.98 GPa, demonstrating excellent application prospects in high-precision and cutting-edge fields such as precision instrumentation.