LaFe_(11.2)Si_(1.8)合金的组织结构与负热膨胀性能  

Structure and Negative Thermal Expansion of LaFe_(11.2)Si_(1.8) Alloy

作　　者：刘艳颖 李雯[2] 黄荣进[2] 肖福仁[1] 李来风[2] 

机构地区：[1]燕山大学,河北秦皇岛066004 [2]中国科学院理化技术研究所航天低温推进剂技术国家重点实验室,北京100190

出　　处：《稀有金属材料与工程》2015年第1期228-231,共4页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51077123;51232004);国家磁约束核聚变能发展研究专项(2011GB112003);航天低温推进剂技术国家重点实验室基金(SKLTSCP1204)

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。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.

关 键 词：LaFe11.2Si1.8合金 负热膨胀 组织 退火 

分 类 号：TB64[一般工业技术—制冷工程]