γ‐Y₂Si₂O₇, a Machinable Silicate Ceramic: Mechanical Properties and Machinability

Abstract

In this paper, the mechanical properties of bulk single‐phase γ‐Y2Si2O7 ceramic are reported. γ‐Y2Si2O7 exhibits low shear modulus, excellent damage tolerance, and thus has a good machinability ready for metal working tools. To understand the underlying mechanism of machinability, drilling test, Hertzian contact test, and density functional theory (DFT) calculation are employed. Hertzian contact test demonstrates that γ‐Y2Si2O7 is a “quasi‐plastic” ceramic and the intrinsically weak interfaces contribute to its machinability. Crystal structure characteristics and DFT calculations of γ‐Y2Si2O7 suggest that some weakly bonded planes, which involve Y–O bonds that can be easily broken, are the sources of the low shear deformation resistance and good machinability.

Preparation, mechanical, and thermal properties of a promising thermal barrier material: Y4Al2O9

“…(5), the damage tolerance of YAM is determined 0.25. This value is slightly lower than those of -Yb 2 Si 2 O 7 (0.39) [14] and -Y 2 Si 2 O 7 (0.37) [15], but still warants the damage tolerance of YAM.…”

Processing and Testing Re2Si207 Matrix Composites (Preprint)

“…6,[9][10] Both are soft (Vickers hardness ~6 GPa) and machineable. However, monazite decomposes in the reducing atmospheres typically used for processing SiC-SiC CMCs, and the rare earth disilicate La 2 Si 2 O powder compacts at their phase formation temperatures of 1000°C -1200°C using pressureless sintering was not successful; therefore, their hardness values were not measured.…”

“…is a "quasi-ductile" ceramic [5][6] and has comparable mechanical properties to LaPO 4 (monazite), which has been demonstrated to function as a weak fiber-matrix interphase in oxide-oxide CMCs. 6,[9][10] Both are soft (Vickers hardness ~6 GPa) and machineable.…”

Microstructure and mechanical properties of h-BN/Y2SiO5 composites

“…Recently, singlephase bulk yttrium silicates have been successfully fabricated and characterized by Sun et al [12,13]. Interestingly, they show moderate hardness (5)(6) and are also belong to the family of "machinable ceramics".…”