Nanoindentation deformation and cracking in sapphire

Abstract

Single crystal sapphire is an anisotropic material and its mechanical behaviour depends on the crystallographic orientation. In this work, a systematic study is performed to investigate the effect of crystallographic orientation on the deformation and cracking of sapphire by means of nanoindentation using spherical indenters. It aims also at determining the physical origin of the "pop-in" appearing in the nanoindentation curves.For that purpose, nanoindentations were performed where the load was increased until

Cause analysis of chatoyancy of sapphires from Shandong, China

“…26 In a previous report, a systematic study was performed to investigate the effect of crystallographic orientation on the deformation and cracking of sapphires by means of nanoindentation using spherical indenters. 27 The study of the composition and properties of deep fluids has become one of the hotspots in recent years. Besides, the fluid components in inclusions or crystal gaps are the real records of the fluids in the earth.…”

Study on the Influence of Sapphire Crystal Orientation on Its Chemical Mechanical Polishing

“…Ma et al [15] studied the crystallographic orientation effect on the incipient plasticity and stochastic behavior of a sapphire single crystal by spherical nanoindentation. Trabadelo et al [16] studied the deformation and cracking behavior of sapphire under spherical nanoindentation for suppling and enriching the existing studies. Manjima Bhattacharya et al [17] did the research to investigate the interaction of nanoscale damages with static and dynamic contact and induced damages in alumina by using nanoindentation.…”

Damage and failure mechanism of sapphire under ballistic loading based on a modified bond‐based peridynamic model

“…Schematic of the relevant preferential crack systems of sapphire on: (A) $$\mathit {a}$$‐plane and (B) $$\mathit {c}$$‐plane, with reference to previous SEM observation 11,61 …”

“…Therefore, for the detailed revelation of the dynamic damage mechanisms of sapphire, we need to recognize some characteristic fracture modes of single‐crystal materials. The results of the nanoindentation experiments on sapphire 11,12,61,62 have declared that the crack systems are crystal orientation‐dependent, the cracks occur and develop along well‐defined orientation, the so‐called preferential direction. Figure 20 illustrates two schematics of the relevant preferential crack systems on the $$\mathit {a}$$‐plane and $$\mathit {c}$$‐plane.…”

“…As the spherical projectile hits the edge surface of the sapphire plate, the area ahead of the projectile will first deform due to compression wave. 11,61 Then, this part of the material rapidly fails and collapses into very fine particles (extremely high levels of crack density) because the high-impact stress induced by point contact exceeds the ultimate compression strength of sap-F I G U R E 2 1 Schematic of damage types and development in sapphire under the spherical projectile phire material. The material comminution phenomenon is often seen in penetration studies, and the part of this area is usually named the comminuted zone or "Mescall zone".…”