Title of article :
Atomic force microscopy study of nanoindentation creep on the (100) face of MgO single crystals
Author/Authors :
Sangwal، نويسنده , , K. and Gorostiza، نويسنده , , P. and Sanz، نويسنده , , F.، نويسنده ,
Issue Information :
هفته نامه با شماره پیاپی سال 2000
Abstract :
The experimental results obtained on nanoindentation creep and evolution of indentation impressions made on the (100) face of MgO crystals from their in-situ observations by atomic force microscopy are described and discussed. The indentations were made by square pyramidal Si tips at a constant load of 2 μN and indentation times, tind, between 0.001 and 10 s. It was found that:1.
itial depth, di, of indentations is practically constant for tind<0.1 s but increases with increasing tind for tind>0.1 s;
itial indentation diameter, ai, practically does not depend on tind;
ented surface always tends to heal with time, but the time, t, of healing increases with penetration depth of d (i.e. on indentation time);
pendences of both d and a on recovery time, t, exhibit three recovery stages — an initial transient stage, a steady-state stage and a slow stage — and follow a power-law dependence in these stages; and
ation creep occurs for tind>0.1 s.
sis of the kinetics suggests that the recovery of indentations and the indentation creep occur by local reorganization, and volume and surface diffusion processes, but the indentation creep is caused above a threshold value of the indentation pressure gradient.
Keywords :
Low-index single crystal surfaces , atomic force microscopy , Magnesium oxide , Single crystal surfaces , Surface relaxation and reconstruction , Surface stress , surface structure , surface diffusion , roughness and topography , morphology
Journal title :
Surface Science
Journal title :
Surface Science