Thermal evolution of deformation zones around microindentations in different types of crystal

Abstract

Several structural levels of plastic deformation (the superdefect zone, the quasidestructured region, the region with a high dislocation density, the peripheral zone and the region of elastic deformation) have been distinguished around microindentations of various crystal types. The real structure of the deformed zone essentially depends on both the crystal type and the deformation temperature. Four temperature stages (brittle, brittle±plastic, plastic and ductile±plastic) have been noted in the wide temperature interval …T …0:1 0:9 †T ml †. It has been revealed that crystals with various types of bond can undergo similar thermal evolution behaviours of the defect structure around the indentation.

Anomalous dissolution of microindentation deformed zone of ITO/Si coated system

“…Similar pronounced cracks accompanied by chips at heavy loads (>2.0 N) were detected when the indentations were made on the Si single crystals. In accordance with [3], the area encircling these cracks corresponds to a quasi-destructured zone. Strong long-range internal stresses are created in this region due to low dislocation mobility and the high dislocation density.…”

“…It was shown to be equal to D ≈ 2.1d for a Vickers indenter. Indeed, numerous experiments confirmed the creation of a similar stress and the appearance of such an elastic/plastic state in various materials under microindentation [3,5,6]. The Ddimension detected above for the 0.5 N indent is commensurable with the theoretical estimation of the elastic/plastic deformed zone; at the same time, it corresponds to the dimensions of the quasi-destructured region around the indentation typical for brittle crystals, such as Si [3].…”

“…Indeed, numerous experiments confirmed the creation of a similar stress and the appearance of such an elastic/plastic state in various materials under microindentation [3,5,6]. The Ddimension detected above for the 0.5 N indent is commensurable with the theoretical estimation of the elastic/plastic deformed zone; at the same time, it corresponds to the dimensions of the quasi-destructured region around the indentation typical for brittle crystals, such as Si [3]. The quasi-destructured region is a zone where the agglomeration of dislocations, dislocation walls, disclinations and point defects takes place, where the most complicated dislocation-disclination reactions occur that lead to the rotation processes, structure fragmentation, material translation, etc.…”

“…In solar cells the In 2 O 3 ּSnO 2 (ITO) films thickness is ~350 nm; the composite microhardness (H V ) of such a CSs is found to be ~ 11.0 GPa and 9.5 GPa for the Si substrate, respectively [2,3]. Thus, this CS can be considered a 'hardon-hard' composite structure.…”

Continuum crystal plasticity analyses of the plastic flow features underneath single-crystal indentations

“…Although these results clearly illustrate the crystallographic component of dislocation gliding, an in-depth analysis of the experiments is difficult to perform given the large dislocation density and intensive dislocation interactions developing under contact loading conditions. Most of the available work on the plastic flow behavior underneath the imprint at the microscale thus comprises semiconductors and ceramics in general with reduced dislocation activity as compared to soft metals [12][13][14][15][16][17]. Discrete dislocation plasticity and molecular dynamics simulations in conjunction with advanced nanomechanical testing techniques have also become available in recent years, enabling investigation of dislocation nucleation events [18][19][20][21][22][23][24][25][26][27][28].…”