Surface Modification of Al₂O₃/TiC Cutting Ceramics

Abstract

Cutting ceramics with a graded TiC‐rich surface have been obtained by an in situ reaction. Al2O3/TiC ceramics, prepared by reaction sintering, have been subjected to various thermal posttreatments at atmospheric pressure. The temperature, dwelling time, and reaction atmosphere have been varied. It has been observed that a TiC‐rich surface develops in CO‐containing atmospheres. The microstructure of the bulk remains unaffected. Thermal treatment under a CO atmosphere at 1600°C for 1 h resulted in a dense TiC layer on the ceramic. A schematic model is proposed for this layer formation process.

Influence of Surface Modification on the Cutting Performance of Reaction‐Sintered Al2O3–TiOC Ceramics

“…Details were reported in our previous publication. 18 The layer thickness in C151C was determined to be 1 mm. The layer formed in C151C is completely dense as compared with that formed in C1510C, which is porous in nature but 1.5 mm thick.…”

“…For surface modifications, these sintered samples were posttreated under a gas atmosphere consisting of Ar and different percentages of CO 2 . Details of the sample preparation have been reported in our previous article 18 . Three types of inserts have been used for cutting experiments: C15 (reaction‐sintered Al 2 O 3 –TiOC), C151C (C15 treated under a 1 vol% CO 2 +Ar atmosphere, 1600°C, 1 h), and C1510C (C15 treated under a 10 vol% CO 2 +Ar atmosphere, 1600°C, 1 h).…”

In situ measurement of lattice strains in mixed ceramic cutting tools under thermal and mechanical loads using synchrotron radiation

“…Bending bars of mixed ceramic material with a composition of approximately 65 wt% Al 2 O 3 , 30 wt% Ti(C,O), and 5 wt% ZrO 2 were fabricated according to standard procedure at the Hamburg University of Technology as described in previous works [19,4].…”

Effect of zirconia and iron on the mechanical properties of Al2O3/TiC composites processed using combined self-propagating synthesis and direct consolidation technique

“…In recent years, Al 2 O 3 -TiC composites have been investigated for structural applications.. The attractive mechanical properties of the composites in this system include high hardness, good flexural strength and high wear resistance, make them suitable candidates in high speed machining tools application [1][2][3]. Commercially, pressure-less sintering and hot-pressing are the most common processing routes used for fabricating these composites [4].…”

“…From the Vickers indents, the micro-hardness, H, the indentation diagonal length, 2a, and micro-crack length, 2c, are measured. These values are then substituted into equation 2 to yield fracture toughness in units of MPa.m1…”