摘要
采用X射线衍射、透射电镜(TEM)和差热分析(DTA)等手段在快速凝固A_(66)Mn_(14)Cu_(20)合金中发现一个二十面体相。这个相的选区电子衍射花样显示出准晶体结构的五次对称性。X射线能谱分析结果表明它是一个成分为Al_(11)Mn_3Cu_6的三元相。差热分析结果反映出这个准晶相有很高的热稳定性。以20K/min的速度加热时,这个相的晶化峰值温度为818K,其转变激活能约为405.7kJ/mol。
An icosahedral phase in a rapidly solidifidd Al_(66) Mn_(14) Cu_(20) alloy is identified by means of X-ray diffraction (XRD), transmission microscope (TEM) and differential thermal analysis (DTA)methods. The selected area diffraction patterns from the phase show a fivefold symmetry of a qua-sierystalline structure. The energy dispersive X-ray spectra (EDXS) for the phase indicate that it is aternary of composition Al_(11) Mn_3 Cu_6. The results of DTA reveal that it has high thermal stability.Its crystalization peak temperature (at heating rate 20 K/min) is 818 K, and the activation energy ofthe transformation is about 405. 7 kJ/mol.
关键词
Al-Mn-Cu
铝合金
凝固
准晶相
aluminium alloy
rapid solidification
quasicrystalline phase
