Fe掺杂MnNiGe合金的热膨胀性能研究

Thermal Expansion Behavior of Fe-Doped MnNiGe Alloys

摘要: 零热膨胀材料在温度变化过程中会表现出优异的尺寸稳定性，在精密仪器、光学系统和航天结构等关键领域具有重要的应用价值。MnNiGe合金在相变过程中会发生显著的晶格畸变引发反常热膨胀效应，被视为潜在的高性能零热膨胀材料。但是其本征脆性强，室温下易自发破碎成粉末状，严重限制了该材料的工程化应用进程。为了解决此问题，本研究采用Fe元素替代Mn，制备了一系列Mn_1-xFe_xNiGe合金；借助X射线衍射仪、扫描电子显微镜、热膨胀仪等仪器研究了该材料的晶体结构、显微结构以及热膨胀特性。研究表明，Mn_0.65NiGeFe_0.35合金表现出宽温域的零热膨胀行为，其线性热膨胀系数低至0.65×10⁻⁶ K⁻¹，同时抗压强度达167 MPa，在精密仪器等领域展现出良好的应用前景。

Abstract: Zero thermal expansion materials exhibit outstanding dimensional stability under temperature variations, holding significant application value in critical fields such as precision instruments, optical systems, and aerospace structures. MnNiGe alloy is considered a promising high-performance zero-thermal-expansion material due to the significant lattice distortion during its phase transition, which induces an anomalous thermal expansion effect. However, its intrinsic brittleness is high, and it tends to spontaneously pulverize at room temperature, severely limiting its engineering application. To address this issue, this study employs Fe element to replace Mn, preparing a series of Mn_1-xFe_xNiGe alloys. Instruments such as X-ray diffractometer (XRD), scanning electron microscope (SEM), and dilatometer are used to investigate the crystal structure, microstructure, and thermal expansion properties of the material. The research indicates that the Mn_0.65NiGeFe_0.35 alloy exhibits zero thermal expansion behavior over a wide temperature range, with a linear thermal expansion coefficient as low as 0.65 × 10⁻⁶ K⁻¹. Meanwhile, its compressive strength reaches 167 MPa, showing promising application prospects in fields such as precision instruments.