Load-dependent indentation behavior of β-SiAlON and α-silicon carbide

Abstract

A comparative study was carried out on the load-dependent indentation behavior with respect to hardness and induced cracks of β-SiAlON and α-silicon carbide ceramics. It is observed that silicon carbide (SiC) exhibits lower transition load, early cracking and severely crushed indentation sites, whereas β-SiAlON shows higher transition load and damage-free indentation zone even at the maximum applied load (294.19 N). Crack density is higher for α-SiC with comparison to β-SiAlON at each load. SiC exhibits both main and secondary radial types of cracking from low indentation load (0.98 N). Cracks are often associated with branching at higher load (> 9.80 N) for α-SiC. β-SiAlON exhibits cracks which are mainly radial types initiated at 4.90 N load. These opposing behaviors of β-SiAlON and α-SiC are attributed to their difference in hardness, toughness, and brittleness index. Higher brittleness of α-SiC results in early and severe cracking around its indentations. β-SiAlON shows less cracking due to its lower brittleness and higher toughness. The increased size of indentation-induced cracks of α-SiC is higher than that of β-SiAlON due to the rapid crack propagation in α-SiC with transgranular fracture behavior.

Influence of binder systems on sintering characteristics, microstructures, and mechanical properties of PcBN composites fabricated by SPS

“…SiAlON ceramics have superior sinterability, excellent mechanical properties, and good high temperature performance including high temperature strength, oxidation resistance, and thermal shock resistance, thereby having widely application prospects as structural components and cutting tools [27,28]. Sample S3 mainly produced new reaction products of TiB 2 , AlB 2 , TiN, AlN, as well as minor amounts of hBN when sintered at 1500 ℃ .…”

Molecular Dynamics Analysis of Subsurface Brittleness Mechanism of Nanocrystalline 3C-SiC Rough Friction Surface

“…The removal, grinding and polishing of 3C-SiC materials by nano-machining technology make the application prospect of 3C-SiC materials more targeted and extensive. However, there are significant differences between nano-grinding and traditional grinding in material removal methods and brittleness mechanism [7][8][9][10][11] . Under the operation requirements of high-precision nano-grinding, it is difficult to control the material processing range, depth and material forming in the process of nano-grinding, and a series of special physical phenomena such as micro-wear and size effect are often produced [12][13][14][15] .…”