利用纳米压痕仪、原子力显微镜以及电子显微镜等性能与显微结构分析手段对镁基二十面体准晶的应变速率敏感性问题进行了研究.在室温下对铸态Mg79.4-Zn18.5-Gd2.1(at.%)合金中形成的网状准晶相进行纳米压入测试,比较了不同压入应变速率下压痕的压入曲线、表面形貌差异,并据此对准晶相的压入变形行为进行了研究.结果表明,准晶相的室温硬度对应变速率敏感,其变形行为与常规金属及合金相比具有特殊性.结合准晶原子团簇摩擦变形理论,对反映准晶特性的压入实验现象进行了分析和讨论.%Mechanical and structural characterizations by means of nanoindentation, atomic force microscope and electron microscopy techniques have been carried out to investigate the strain rate sensitivity of Mg-based icosahedral quasicrystal. Nanoindentation testing for the dendritic icosahedral quasicrystal phase formed in the as-cast Mg79. 4-Zn18. 5-Gd2. 1 ( at.%) alloy was performed at different strain rates, through which variations of indentation curves and surface morphological features were compared, and furthermore the associated indentation deformation behaviors were revealed. The results showed that the hardness of the Mg-Zn-Gd icosahedral quasicrystal phase is sensitive to strain rate, and that the quasicrystal phase can behave with some special indentation features in contrast to those common metals and alloys. Based on the cluster friction theory of quasicrystal deformation, the indentation phenomena with particularity of the Mg-Zn-Gd quasicrystal phase have been analyzed and discussed.
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