טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentKhoptiar Yuri
SubjectReactive in Situ Synthesis of Layered Machinable Ti-Based
Ternary Ceramic Matrix Composites
DepartmentDepartment of Materials Science and Engineering
Supervisors Professor Elazar Gutmanas
Dr. Irena Gotman
Mr. Leonid Klinger


Abstract

Self-propagating High-temperature Synthesis (SHS) is an attractive method of ceramic materials’ synthesis based on utilizing the exothermic heat of their formation.  Ti3SiC2, Ti2AlC and Ti3AlC2 carbides belong to a remarkable group of machinable layered ternary ceramics, that combine the features of ceramics with those of metals and are recognized as potentially attractive materials for various functional and structural applications.  The overall goal of the present research was to obtain a good understanding of the reactive processes underlying the SHS synthesis of layered ternary carbides from the corresponding elemental powders.  In particular, the fabrication of fully dense near-net shape products via pressure-assisted thermal explosion mode of SHS has been addressed.

In each elemental powder blend SHS was performed via both combustion wave propagation and thermal explosion.  By monitoring the temperature during SHS synthesis, heating curves were obtained.  The products were characterized using X-ray diffraction and scanning electron microscopy with electron probe microanalysis.  Based on the results, reaction sequences during the SHS synthesis of each ternary compound have been proposed.

Dense (95 - 99 %) near-net shape products were fabricated employing the original method of Reactive Forging within a confinement cylinder.  In particular, a near fully dense material containing ~ 90% Ti3AlC2 was successfully synthesized.  The material was found to possess a finer grain size and higher compressive strength compared to reports in literature.

The results of the research can be further used for the modeling of SHS processes in three-component powder blends as well as serve a scientific base for the development of practical processing routes for layered ternary compounds and their composites.