Relationship between microstructure and abrasive wear resistance of Al2O3–FeAl2O4 nanocomposites produced via solid-state precipitation

Processing of Alumina and Corresponding Composites

“…As discussed before for Al 2 O 3 -SiC w composites (Section 2.02.4.2.2), the incorporation of the high bond energy second phases such as the SiC nanoparticles severely inhibits sintering (Mukhopadhya & Basu, 2007;Mukhopadhyay & Todd, 2011;Sternitzke, 1997).…”

“…In general, it is necessary to start from a nanosized second phase that would react with the matrix particles during sintering process. Al 2 O 3 -FeAl 2 O 4 nanocomposites, with improved wear resistance as compared to that of single-phase alumina with similar grain sizes, have been produced by solidstate precipitation during the aging of Al 2 O 3 -10 wt% Fe 2 O 3 solid solutions in reducing atmosphere (Mukhopadhyay & Todd, 2010a;Mukhopadhyay & Todd, 2011). The microstructure of the materials was further improved by doping with 250 ppm Y 2 O 3 (Mukhopadhyay & Todd, 2010b.…”

Wear Behavior of Bulk Polycrystalline MgO–MgFe2O4 “Age‐Hardened Alloys”

“…The critical size of the MgFe 2 O 4 second phase particles that might lead to weakening and spontaneous cracking upon cooling from the aging temperature, as estimated using the relevant relations based on co‐efficient of thermal expansion mismatch (~5.5 × 10 −6 here), is ~400 nm. Hence, the MgFe 2 O 4 particle sizes in these alloys, especially those formed upon aging for 0 h, are not expected to have any detrimental effect.…”

“…It may be recalled here that dominant role of plastic deformation in wear damage of MgO has been highlighted in the few earlier studies on sliding wear of single crystals. In addition, presence of intragranular second phase particles (SiC or FeAl 2 O 4 ) in Al 2 O 3 have also been associated with improvements in wear resistance via suppression of grain pull‐out, which is sometimes believed to be due to interactions of the particles with the matrix dislocations/twins …”

“…The wear rates ( v ) were estimated using the following equation;where, A is the contact area, ρ is the specimen density and t is the test duration (20 and 100 s). Similar set‐up and methodology were earlier used for investigations of abrasive wear resistances of Al 2 O 3 ‐based nanocomposites . The worn surfaces, as well as polished cross sections of the worn samples, were observed in FEG‐SEM (JEOL JSM‐7600F, Tokyo, Japan).…”