中文摘要：

通过X射线衍射仪和扫描电子显微镜研究了不同退火工艺的LaFe11.2Si1.8合金的微观组织,并采用热膨胀系数测试仪测试了其膨胀性能。结果表明：经过1200℃退火5 h的试样获得了含一定量α-Fe杂相的组织;经1050℃退火15 d和1100℃退火2 d均获得了NaZn13型La（Fe,Si）13纯相的晶体结构。LaFe11.2Si1.8合金的负膨胀量与La（Fe,Si）13相的含量成正比,纯相试样的负膨胀量达到最大,其ΔL/L值为3.22×10^-3,负热膨胀系数α=–39.31×10^-6 K^-1。

英文摘要：

Microstructure and thermal expansion coefficient of LaFe11.2Si1.8 alloy in different annealing processes were investigated by X-ray diffraction, scanning electron microscope and thermo-dilatometer. The results show that the sample annealed at 1200 oC for 5 h contains a certain amount of α-Fe phase, while the samples annealed at 1050 oC for 15 d and at 1100 oC for 2 d form a single La（Fe,Si）13phase with the NaZn13 structure. The magnitude of the negative thermal expansion is linear with the La（Fe,Si）13 phase content. Typically, the magnitude of the negative thermal expansion and thermal expansion coefficient of the samples annealed at 1050 oC for 15 d are 3.22×10^-3 and –39.31×10^-6 K^-1, respectively.