Evidence for dislocation-controlled crater wear of polycrystalline aluminum oxide cutting tools

Abstract

Transmission electron micrographs are presented which show evidence of plastic deformation in the form of high densities of dislocations and twins in the subsurface of the crater area of polycrystalline alumina cutting tools. The inverse dependence of crater area on hardness for four different tool materials suggests that plastic flow controls the rate of crater wear.

ECCI, EBSD and EPSC characterization of rhombohedral twinning in polycrystalline α-alumina deformed in a D-DIA apparatus

“…Microstructural characterization of rhombohedral twins in deformed alumina has been primarily performed using transmission electron microscopy (TEM) (Hockey, 1971;Kim et al, 1973;Grimmer et al, 1990;Korinek & Castaing, 2003;Lartigue-Korinek et al, 2008;Barber & Tighe, 1965;Castaing et al, 2000). Deformation twins can also be characterized quantitatively in a SEM using electron channeling contrast imaging (ECCI) coupled with electron backscatter diffraction (EBSD).…”

“…Alumina (aluminium oxide, -Al 2 O 3 ) is the most commonly used engineering ceramic for structural applications (Badmos & Ivey, 2001), including for wear resistance (Medvedovski, 2001;Milak et al, 2015), armor (Medvedovski, 2006(Medvedovski, , 2010Walley, 2010;Silva et al, 2014), automotive, industrial and aerospace engineering, biomedical applications (Silvestre et al, 2015), and cutting tools (Kim et al, 1973;Senthil Kumar et al, 2003, 2006. The wide range of applications of alumina ceramics is a result of their availability and low cost as well as their excellent combination of mechanical and thermal properties.…”