Size-dependent plasticity in micron- and submicron-sized ionic crystals

作者：Zou Yu; Spolenak Ralph^*

来源：Philosophical Magazine Letters, 2013, 93(7): 431-438.

DOI：10.1080/09500839.2013.797616

• compression
• ionic crystals
• mechanical properties
• ion irradiation
• size effects

Uniaxial microcompression methodology is applied to study the mechanical behaviour of 100-oriented NaCl, KCl, LiF and MgO single-crystal pillars ranging from 250nm to 4m in diameter. As in metallic materials a strong size effect with regard to compressive strength is observed, NaCl, KCl, LiF and MgO pillars exhibit scaling exponents of -0.64 +/- 0.02, -0.72 +/- 0.02, -0.68 +/- 0.02 and -0.8 +/- 0.03, respectively. These compare well to face centered cubic (fcc) metals, but the normalized stress levels of LiF and MgO are higher than those of NaCl, KCl and fcc metals. The differences in strength levels are interpreted in terms of susceptibility to ion-induced damage, which is intrinsic to the fabrication process. In addition, the strong size-dependent plasticity of 100-oriented ionic crystals can be correlated with their lower critical temperatures.

• 出版日期2013-7-1