铸锭凝固组织对相应非晶合金晶化过程中二十面体准晶相形成动力学的影响

Influence of the ingot solidification microstructure on the formation kinetics of icosahedral quasicrystalline phase during the crystallization of the corresponding amorphous alloy

通过在真空电弧熔炼炉内对合金铸锭进行反复熔炼处理,获得到了凝固组织不同的Zr65Al7·5Cu12·5Ni10Ag5合金铸锭.在相同的制备条件下,由凝固组织不同的合金铸锭通过吸铸法制备得到了薄片非晶合金.利用差示扫描量热法(DSC)对非晶合金的晶化动力学进行了分析.x射线衍射谱表明,在Zr65Al7·5Cu12·5Ni10Ag5非晶合金晶化过程中,二十面体准晶相(I相)作为初生相析出.Kissinger分析结果表明,合金铸锭的凝固组织细化,相对应的非晶合金发生晶化时,I相形成与分解的有效激活能都增大,说明非晶合金及析出的I相的热稳定性都提高.从结构的遗传性角度就合金铸锭凝固组织对相应非晶合金晶化过程中二十面体准晶相的形成动力学的影响进行了讨论.

Zr65Al2.5Cu12.5Ni10Ag5 ingots with different solidification microstructures are obtained by repeated are melting of origin ingots. Under the same conditions, slices of amorphous alloys can be produced by suction casting in a copper mold. Differential scanning calorimetry （DSC） is employed to investigate the crystallization kinetics of the amorphous alloys. X-ray diffraction pattems （XRD） show that icosahedral quasicrystalline phase （Ⅰ-phase） precipitates as primary phase during the crystallization of Zr65Al2.5Cu12.5Ni10Ag5 amorphous alloys. The results of Kissinger analyses suggest that the amorphous alloys made from the ingot with finer microstructure show better thermal stability, and that the Ⅰ-phase precipitated becomes more stable against decomposition. Within the frame of structure heredity, the influence of ingot microstructure on the formation kinetics of Ⅰ-phase during the crystallization of corresponding amorphous alloys is discussed.