中文摘要：

采用电弧熔炼和高能球磨以及回火热处理工艺制备了Mn（55）Al（45）合金粉体,使用SEM、XRD和网络矢量分析仪分析了球磨时间和回火温度对Mn（55）Al（45）合金微粉的形貌、相结构及吸波性能的影响。结果表明：随球磨时间增加,粉体中Al2Mn3和Al（11）Mn（14）的相对含量会随之而增加;粉体的复介电常数虚部、复磁导率虚部的共振峰频率和吸收峰频率都随球磨时间的增加而逐渐向低频移动,球磨18 h的粉体有很好的频宽效果;球磨24 h时,反射率峰值在16 GHz处达到-28 dB。随回火温度的增加,粉体中的Al2Mn3增多,球磨18 h后和经400℃回火处理的粉体,在6~18 GHz频段内有较好的综合吸波性能。在吸波涂层厚度d=2.0 mm下,400℃回火处理的粉体在17 GHz频率处具有最小反射率值为-26.4 dB。

英文摘要：

Mn（55）Al（45） alloy powder was prepared by the combined use of arc melting,high energy ball milling and tempering heat treatment process.The phase structure and the microstructure of the alloy powder were analyzed by X-ray diffraction（XRD） and scanning electron microscopy（SEM）,and then their microwave absorbing properties were tested by a vector network analyzer.The results show that an increase of phases for Al2Mn3 and Al（11）Mn（14） are accompanied by the increased milling time;the resonant frequency and the absorption peaks of ε ＂ and μ＂ shift towards lower frequency region simultaneously.A better result of electromagnetic properties is brought to the alloy powder when the ball milling time is set to 18 h in first attempt.While the ball milling time is increased to 24 h during later experiment,the minimum reflectivity value reaches to-28 dB at a frequency of 16 GHz.The Al2Mn3 phase increases with an artificial increase of tempering temperature.The Mn（55）Al（45） alloy powder ball milled for 18 h and tempered at 400 ℃ exhibits preferably comprehensive microwave absorbing properties in the range of 6~8 GHz.The minimum reflectivity value and absorption peak frequency at the coating thickness of 2.0 mm are-26.4 dB,17 GHz,respectively.